There is no reason for them to run on the main thread, it's safe to call
AVFoundation functions on threads other than the main thread.

The previous code made an incorrect claim about the thread in which the audio
route change notification selector is called: it's called on a secondary thread:
https://developer.apple.com/documentation/avfoundation/avaudiosessionroutechangenotification

Fix the "mute ping pong" for once and for all. This patch takes a new approach
to the problem: it keeps track of the user generated CallKit transaction ations
and avoids calling the delegate method in those cases.

This results in a much cleaner and easier to understand handling of the flow: if
the delegate method is called it means the user tapped on the mute button. When
we sync the muted state in JS with CallKit the delegate method won't be called
at all, thus avoiding the ping-pong altogether.

In addition, make sure all CallKit methods run in the UI thread. CallKit will
call our delegate methods in the UI thread too, thsu there is no need to
synchronize access to the listener / pending action sets.

Fixes the following warning:

~~~
Module XXX requires main queue setup since it overrides `constantsToExport` but doesn't implement `requiresMainQueueSetup`. In a future release React Native will default to initializing all native modules on a background thread unless explicitly opted-out of.
~~~

For AppInfo and AuioMode, there is no need to initialize anything in the UI
thread, so just return NO.

Fixes: https://github.com/jitsi/jitsi-meet/issues/3086

This happend after initialization and joining a conference for the first time
in JitsiMeetView.

With this the RN component and the consumer app can share same CallKit
provider, configuration, and enable to be part of multiple listeners of
the CallKit flow events. The main driver of this is to enable the
consumer app to be able to report an incoming call to the OS before
loading the JitsiMeetView. Once the user answers the call, the app can
instantiate a JitsiMeetView, pass the CallKit call UUIID, and the Jitsi
Meet components will handle the connection and report back to CallKit
that the  call has been established.

If the beginAddPeople delegate method is implemented, and they haven't been
explicitly set to NO, they willbe YES.

* 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>

On Android the files will be copied to the assets/sounds directory of
the SDK bundle on build time. To play the "asset:/" prefix has to be
used to locate the files correctly.

On iOS each sound file must be added to the SDK's Xcode project in order
to be bundled correctly. To playback we need to know the path of the SDK
bundle which is now exposed by the AppInfo iOS module.

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.

Story time.  Currently the app can be started in 4 ways:

- just tapping on the icon
- via a deep link
- via a universal link
- via the phone's recent calls list

The last 3 options will make the app join the specified room upon launch. React
Native's Linking module implements the necessary bits to handle deep or
universal linking, but CallKit is out of its scope.

In order to blend any type of app startup mode, a new LaunchOptions module (iOS
only) exports a getInitialURL function, akin to the one in the Linking module,
but taking CallKit instents into consideration. This function is then used to
make app startup with a URL consistent across all different modes.

Fixes: #2377 #2267 #2158

Due to the difference in nature, the iOS and Android implementations are
completely different:

iOS: MPVolumeView is used, which allows us to place a button which will launch a
native route picker provided by iOS itself. This view is different depending on
the iOS version, with the iOS 11 version being more complete.

Android: A completely custom component is used, which displays a bottom sheet
with the device categories, not devices individually. This is akin to the sheet
in the builtin dialer.

The root view was not adjusting it's bounds after device rotation.

Revert "[RN] Remove unnecessary source code" (commit
a3441030a3). But since the project file
needs to explicitly mention the CallKit and Intents framework, do not
use the semantic @import as that's confusing in the case.

* Javadoc introduced @code as a replacement of <code> and <tt> which is
  better aligned with other javadoc tags such as @link. Use it in the
  Java source code. If we switch to Kotlin, then we'll definitely use
  Markdown.

* There are more uses of @code in the JavaScript source code than <tt>
  so use @code for the sake of consistency. Eventually, I'd rather we
  switch to Markdown because it's easier on my eyes.

* Xcode is plain confused by @code and @link. The Internet says that
  Xcode supports the backquote character to denote the beginning and end
  of a string of characters which should be formatted for display as
  code but it doesn't work for me. <tt> is not rendered at all. So use
  the backquote which is rendered itself. Hopefully, if we switch to
  Markdown, then it'll be common between JavaScript and Objective-C
  source code.

This commit adds initial support for CallKit on supported platforms: iOS >= 10.

Since the call flow in Jitsi Meet is basically making outgoing calls, only
outgoing call support is currently handled via CallKit.

Features:
 - "Green bar" when in a call.
 - Native CallKit view when tapping on the call label on the lock screen.
 - Support for audio muting from the native CallKit view.
 - Support for recent calls (audio-only calls logged as Audio calls, others show
   as Video calls).
 - Call display name is room name.
 - Graceful downgrade on systems without CallKit support.

Limitations:
 - Native CallKit view cannot be shown for audio-only calls (this is a CallKit
   limitaion).
 - The video button in the CallKit view will start a new video call to the same
   room, and terminate the previous one.
 - No support for call hold.

It provides access to the app's display name and version.

Based on work authored by Shuai Li <sli@atlassian.com>, Daniel Ornelas
<dornelas@atlassian.com>, and Lyubo Marinov <lmarinov@atlassian.com>.