Co-authored-by: Pawel Domas <pawel.domas@jitsi.org>

Use subscribers to detect state change and emit those
out to other participants. Use middleware to register
the command listener.

There is no need for AbstractApp to require some getWindowLocation function.
It's only used in one place and we even polyfill it on mobile.

Thus replace it's usage with more specific functions.

It's now all handled in the SDK an we'll get the new URLs via props.

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

Instead of handling the side effect of navigating to another
url from within componentWillReceiveProps, try to match the
same logic instead in componentDidUpdate.

componentWillMount is a deprecated lifecycle method;
componentDidMount should be used to kick off things
like ajax. In the case of the _App hierarchy, a promise
chain is used to perform initialization, and it is
first started in the constructor by initializing
storage. However, by the time storage is initialized,
resolving the first promise, _App has already mounted.
So, move it all to the componentDidMount lifecycle.

There doesn't seem to be a strong need for the initialized React
Component state in BaseApp so remove/delete it.

BaseApp does all the heavy-lifting related to creating the redux store,
navigation, and so on.

App currently handles URL props and actually triggering navigation based on
them.

Move it away from AbstractApp into an auxiliary function. In addition, introduce
a new `getServerURL` function which gets the configured server URL and defaults
to meet.jit.si as before.

It was never used in practice, and it would be very cumbersome to use, since it
would have to bcreated with all the middlewares and reducers we need. After
discussing this with Lyubomir, we are confident this is not going to be needed
so it can go.

Unfortunately, as the Jitsi Meet development evolved the routing mechanism
became more complex and thre logic ended up spread across multiple parts of the
codebase, which made it hard to follow and extend.

This change aims to fix that by rewriting the routing logic and centralizing it
in (pretty much) a single place, with no implicit inter-dependencies.

In order to arrive there, however, some extra changes were needed, which were
not caught early enough and are thus part of this change:

- JitsiMeetJS initialization is now synchronous: there is nothing async about
  it, and the only async requirement (Temasys support) was lifted. See [0].
- WebRTC support can be detected early: building on top of the above, WebRTC
  support can now be detected immediately, so take advantage of this to simplify
  how we handle unsupported browsers. See [0].

The new router takes decissions based on the Redux state at the time of
invocation. A route can be represented by either a component or a URl reference,
with the latter taking precedence. On mobile, obviously, there is no concept of
URL reference so routing is based solely on components.

[0]: https://github.com/jitsi/lib-jitsi-meet/pull/779

Fragment now works on both React and React Native, so use it.

The goal will be to make video layout stateless and instead
get all state from redux.

"Middleware" redux state changes, not actions.

* 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>

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.

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.

It's detected based on a size threshold.

We started on the way to responsive UI and its design with aspect ratio
and keeping the filmstrip on the short side of the app's visible
rectangle.

Shortly, we're going to introduce reduced UI for Picture-in-Picture. And
that's where we'll need another dimensions-based detector akin to the
aspect ratio detector.

While the AspectRatioDetector, the up-and-coming ReducedUIDetector, and
their base DimensionsDetector are definitely separate abstractions and
implementations not mixed for the purposes of easy extensibility and
maintenance, the three of them are our building blocks on top of which
we'll build our responsive UI.

[RN] Fix PR feedbacks, write persistency docs