Add JitsiMeetFragment and refactor the app to use it.

The android.telecom.CallAudioState class was only added in API level 23 (Android
M), so make sure we don't import it in lower versioned devices.

We are going to implement the invite dialog *inside* the SDK, so there is no
need to have all this machinery anymore.

* feat(Android): implement ConnectionService

Adds basic integration with Android's ConnectionService by implementing
the outgoing call scenario.

* ref(callkit): rename _SET_CALLKIT_SUBSCRIPTIONS

* ref(callkit): move feature to call-integration directory

* feat(ConnectionService): synchronize video state

* ref(AudioMode): use ConnectionService on API >= 26

Not ready yet - few details left mentioned in the FIXMEs

* feat(ConnectionService): add debug logs

Adds logs to trace the calls.

* fix(ConnectionService): leaking ConnectionImpl instances

Turns out there is no callback fired back from the JavaScript side after
the disconnect or abort event is sent from the native. The connection
must be marked as disconnected and removed immediately.

* feat(ConnectionService): handle onCreateOutgoingConnectionFailed

* ref(ConnectionService): merge classes and move to the sdk package

* feat(CallIntegration): show Alert if outgoing call fails

* fix(ConnectionService): alternatively get call UUID from the account

Some Android flavours (or versions ?) do copy over extras to
the onCreateOutgoingConnectionFailed callback. But the call UUID is also
set as the PhoneAccount's label, so eventually it should be available
there.

* ref(ConnectionService): use call UUID as PhoneAccount ID.

The extra is not reliable on some custom Android flavours. It also makes
sense to use unique id for the account instead of the URL given that
it's created on the per call basis.

* fix(ConnectionService): abort the call when hold is requested

Turns out Android P can sometimes request HOLD even though there's no
HOLD capability added to the connection (what!?), so just abort the call
in that case.

* fix(ConnectionService): unregister account on call failure

Unregister the PhoneAccount onCreateOutgoingConnectionFailed. That's
before the ConnectionImpl instance is created which is normally
responsible for doing that.

* fix(AudioModeModule): make package private and run on the audio thread

* address other review comments

This makes Dropbox work on apps using the SDK without needing to build it
themselves.

Provide a default and builtin default implementation which finishes the
Activity, same as before.

What this PR removes is the ability to provide a custom default handler because
applications can already take this decision when calling `onBackPressed`. In
addition, make `onBackPressed` return `void` because it's virtually impossible
for it to return `false` (that would mean that there is no
`ReactInstanceManager`, which means there is no app to begin with).

In addition, remove the use of `BackAndroid` since `BackHandler` contains an iOS
shim now.

The upstream package has been unmaintained for 2 years now, and making the litle
changes needed as React Native needs them is getting old. The actual
funcionality is a couple of one-liners plus tons of boliterplate, which gets
reduced by quite a bit if we just embed it. So here it goes.

Since this is a feature implemented in the SDK, it makes sense that all the
plumbing required to make it work it's in the SDK itself.

This makes the PermissionsAndroid builtin module work.

Introduce the JitsiMeetActivityInterface, which defines the interface that
activities using JitsiMeetView directly must implement in order to ensure full
functionality.

Use react-native-fastimage, which uses 2 full-native image impleentations using
well known and mature (native) libraries.

This gets us rid of 2 libraries which were observerd as a source of bugs and
created trouble with dependencies: react-native-fetch-blob and
react-native-img-cache. They are also no longer well maintained.

It's a separate view (on the native side) and app (on the JavaScript side) so
applications can use it independently.

Co-authored-by: Shuai Li <sli@atlassian.com>
Co-authored-by: Pawel Domas <pawel.domas@jitsi.org>

As the need for adding more views connected with our React code arises, having
everything in JitsiMeetView is not going to scale.

In order to pave the way for multiple apps / views feeding off the React side,
the following changes have been made:

- All base functionality related to creating a ReactRootView and layout are now
  in BaseReactView
- All Activity lifecycle methods that need to be called by any activity holding
  a BaseReactView are now conveniently placed in ReactActivityLifecycleAdapter
- ExternalAPIModule has been refactored to cater for multiple views: events are
  delivered to views, and its their resposibility to deal with them
- Following on the previous point, ListenerUtils is a utility class for helping
  with the translation from events into listener methods

The API to gather these was introduced in API level 26.

Activity.enterPictureInPictureMode method must be invoked synchronously
on userLeaveHint callback in order to be sure that the current Activity
is still visible (does not transit to PAUSED state). Previously if the
asynchronous processing would be delayed enough for the Activity to go
into the PAUSED state it will be too late to go into the PiP mode.

* Button conditionally shown based on if the feature is enabled and available
* Hooks for launching the invite UI (delegates to the native layer)
* Hooks for using the search and dial out checks from the native layer (calls back into JS)
* Hooks for handling sending invites and passing any failures back to the native layer
* Android and iOS handling for those hooks

Author: Ryan Peck <rpeck@atlassian.com>
Author: Eric Brynsvold <ebrynsvold@atlassian.com>

Activity.enterPictureInPictureMode can fail for a couple of reasons
mentioned in the JSDoc:

"The system may disallow entering picture-in-picture in various cases,
including when the activity is not visible, if the screen is locked or
if the user has an activity pinned."

It seems to be safe to assume that those cases will be caught by
a RuntimeException handler (only RuntimeExceptions can be left without
explicit catch block).

Anyway the root cause for problems is the fact that the current process
for going to the picture in picture mode is not synchronised with
Activity's lifecycle. On Activity's "userLeaveHint" callback we dispatch
async task to the JS code which only then after dispatching some more
stuff eventually call native method that enter PiP. In case we spend too
much time on the JS side and the Activity goes to PAUSED state the call
will fail with IllegalStatException: "activity is not visible",
"activity is paused" etc. This means with this fix the app will not
crash, but we'll see it sometimes not go to the PiP mode as expected.

Adds Nat64InfoModule which resolves IPv6 addresses for IPv4 addresses
in IPv6 only network where jitsi-meet deployment does not provide any
IPv6 addresses as ICE candidates.

Adds base/sounds feature which allows other features to register a sound
source under specified id. A new SoundsCollection component will then
render corresponding HTMLAudioElement for each such sound. Once "setRef"
callback is called by the HTMLAudioElement, this element will be added
to the Redux store. When that happens sound can be played through the
new 'playSound' action which will call play() method on the stored
HTMLAudioElement instance.

java.lang.RuntimeException: Tried to access a JS module before the React instance was fully set up. Calls to ReactContext#getJSModule should only happen once initialize() has been called on your native module.
	at com.facebook.react.bridge.ReactContext.getJSModule(ReactContext.java:102)
	at com.rnimmersive.RNImmersiveModule.emitImmersiveStateChangeEvent(RNImmersiveModule.java:74)
	at org.jitsi.meet.sdk.JitsiMeetView.onWindowFocusChanged(JitsiMeetView.java:504)
	at android.view.View.dispatchWindowFocusChanged(View.java:10257)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1193)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1197)
	at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3602)
	at android.os.Handler.dispatchMessage(Handler.java:102)
	at android.os.Looper.loop(Looper.java:154)
	at android.app.ActivityThread.main(ActivityThread.java:6119)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

This only works automatically on Android >= 8. On other platforms / versions, it
relies on the SDK user on implementing a "reduced UI" mode and reacting to the
"request PIP" delegate method.

On Android we go into "immersive mode" when in a conference, this is our way of
being full-creen. There are occasions, however, in which Android takes us out of
immerfive mode without us (the application / SDK) knowing: when a child activity
is started, a modal window shown, etc.

In order to be resilient to any possible change in the immersive mode, register
a listener which will be called when Android changes it, so we can re-eavluate
if we need it and thus re-enable it.