Fixes running profile builds.

The notification is posted by a foreground service, which also has the nice
side-effect of keeping the app alive for a long time.

It may be called in the Activity instead of in the Fragment. Handle both.

At the moment it includes:

- display name
- email
- avatar URL

This information is used *only* if no token was specified.

A libre build will exclude the following:

- Analytics modules
- Google Play services GMS
- Crashlytics
- Firebase

It's a number whichb must be ever increasing with each build submitted to the
store.

Automate its value by using the number of seconds since 1st of January 2019.
That should be enough for ~680 years.

When running the app from Android Studio the React packager is not automatically
started. In vanilla RN projects this is done by the "react-native run-android"
command, but often times it is desired to run from Android Studio.

This fixes that by starting the packager from Gradle.

Consolidate all failure cases into a single one: CONFERENCE_TERMINATED. If the
conference ended gracefully no error indicator will be present, otherwise there
will be.

It renders a single JitsiMeetFragment which holds the JitsiMeetView view.

Co-authored-by: Saúl Ibarra Corretgé <saghul@jitsi.org>

Add JitsiMeetFragment and refactor the app to use it.

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

These values must match these ones in React Native:
5939d078a0/ReactAndroid/src/main/java/com/facebook/react/modules/systeminfo/AndroidInfoHelpers.java (L20-L22)

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.

Note that Android 9 Pie (API 28) disallows HTTP requests by default, so an
exception was needed in the app in order for the Metro bundler to work in debug
mode.

Glide (which is used by react-native-fast-image) can cause trouble if the host
app (the one using the SDK) is using Glide already.

To avoid this, don't use the builtin AppGlideModule (as the docs recommend) and
let apps define it.

Set them to the next release versions. In additon, the buildNumber variable will
be used to match the requirements of versionCode:
https://developer.android.com/studio/publish/versioning

that is, a monotonically increasing number, independent of the app / sdk
version.

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.

LeakCanary is a memory leak detection library which will run only in Debug mode.

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.

This reverts commit 9e0fee6c7d.

WebRTC requires Java 8, and Java 7 is now considered unsupported:
https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/discuss-webrtc/V1h2uQMDCkA/RA-uzncVAAAJ