This is done to kill off the last deprecated lifecycle
usage. There is special logic within index.native to get a
default meeting url by asynchronously fetching it, if
a url is not passed initially. The url is then put onto
state and overridable on subsequent prop updates.

This is mostly implemented in the app, with the needed support in the SDK. Since
the app needs to donate intents and deal with creating NSUserActivity objects it
doesn't feel right to do this in a library. Instead, we donate the intents from
the app, but the SDK is ready to extract conference URLs from any intent which
was registered as a conference activity.

This also opens the door for eventually adding Handoff support.

Share the code for extracting the URL for conference from a NSUserActivity.

chore(deps): bump lib to fix json message type overrriding

Ref: #3543

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.

This is done at the app level, not the SDK.

Currently 2 Firebase services are used:

  - Crashlytics
  - Dynamic Links

They are enabled in tandem, if the appropriate Google services file
(GoogleService-Info.plist on iOS or google-services.json on Android) is found.

Each service needs to be individually enabled in the Firebase console.

The annotation processor is required for our Glide module to be included.

Mention the availability of CocoaPods.

misc: drop dependency on prop-types and polyfill

deps: update webpack loaders

ref(hangup): clean up some UI state on hangup

ref(app): move url change handling to componentDidUpdate

We no longer need it since Rect 16 takes care of passing the context around.
It's also deprecated: https://atlaskit.atlassian.com/packages/core/layer-manager

- bump expose-loader to 0.7.5
- remove unused file-loader

NOTE: The first incarnation of this commmit also removed string-replace-loader,
but alas lib-jitsi-meet lists it as a devDependency so it's not installed and we
are currently running webpack on install. This is arguably wrong, but that's a
discussion for another day.

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

Also update the bundle ID since we don't release with that anyway.

Touch feedback manifests in some ugly black border bleeding out of the thumbnail
itself. Since we already provide feedback (be that by adding the blue border in
case of pinning, or showing the menu in case of long press) the perception is
the same, without the graphical glitch.

- Change the existing overrides to move the flags
  so the first flag does not cover the toolbar.
- Add a new override to disable the slide in
  animation, as it will play for each flag once
  it becomes the first flag--instead of playing
  only once when the flag queue has items.

A CSS override prevents atlaskit theme from setting a
dark background on the top toolbar. With the upgrade
of the theme package the CSS class names changed.

- Reset some state on the singletons conference
  and VideoLayout.
- Add a way for LocalVideo to clean itself up
  by sharing logic with the other SmallVideos.
- Add clearing of chat messages so they don't
  linger.
- Remove some UI event listeners.

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.

ref(welcome-page): remove unused atlaskit overrides

WelcomePage used to use @atlaskit/tabs to switch between
recent meetings and calendar meetings. @atlaskit/tabs is
no longer used there so remove the css hacks which made
it look more presentable.

* Fix LoginDialog hidden by gUM-Overlay

Running FF46 on Linux and Android. The gUM Dialog (zIndex 1013) hides the LoginDialog (zIndex 999 by default) , but the gUM Dialog will only be resolved when connection is completed (aka hideUserMediaPermissionsGuidanceOverlay is called once the Promise.all in createInitialLocalTracksAndConnect is resolved and that Promise includes "connect").

Fix this by increasing the connection dialog zIndex.

Alternatively this could by fixed by handling gUM and connection one after the other.

* remove whitespace change

chore(dep): bump @atlaskit/modal-dialog 6.0.12 to 7.1.2

Adds the component which receives the messages from client and a module which enabled on a virtual host will start advertising the component. When clients discover the component they will send message to the component with the name of the room where the dominant speaker event happen.

The package now requires using a ModalTransition component
to handle animations. The existing DialogContainer component
has been split into native and web implementations to support
this change.