* fix(welcome-page): css tweaks in prep for branded welcome page

- Watermarks should no longer depend on toolbar size. The left watermark made
  room for the toolbar when the toolbar was on the left side of the screen, but
  the toolbar has been moved to the bottom. The right watermark...well it'll
  clash with the vertical filmstrip but at least the margins will be consistent
  with the left watermark.
- Apply new font-family so fonts are more likely to be consistent across the
  app. Design likes SF UI and keeps requesting it so use it by default.
- Change sizings of welcome page header to be more responsive. This will help
  the header be scrollable when there is no additional content and the header
  overflows.
- Change colors of the welcome page header and remove background image that
  was in the header. Leave in the dom for the background image in case other
  deployments need to continue showing an image.
- Add a period to the title of the welcome page.
- Move watermarks dom location as it is not part of the header; it's part of the
  whole page.

* [squash] Size and font adjustments. Renaming.

* ref(large-video): combine selectParticipant logic from web

Currently native/middleware/redux has its own logic for selecting a participant
on the bridge. To have the logic web respect that logic, a few changes are
needed.
- Web no longer has its own call to selectParticipant.
- To keep in line with web logic selectParticipant action should act even when
  there is no track. This makes it so that when a participant does get a track
  that the bridge will send high quality. The bridge can already handle when the
  selected participant does not have a video track.
- The timing of web is such that on joining an existing conference, a
  participant joins and the participant's tracks get updated and then the
  conference is joined. The result is selectParticipant does not get fired
  because it no-ops when there is no conference. To avoid having to make
  uncertain changes (to be lazy), update the selected participant on conference
  join as well.

* squash: update comment, pass message to error handler

* fix(dial-in): allow scroll on dial in info page

* squash: some more tweaks for flexible sizing

This version uses a worker queue for all WebRTC operations in iOS.

It will only be requested if a user joins a meeting or flips the switch from
video to audio and back, but never as the first thing when the welcome page is
mounted.

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>

Small reorganization so other features can send events to the native side.

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

* Show subtitles when Jigasi sends transcription results in JSON

* fix: Import PropTypes from prop-types.

* apply feedback on initial PR

* Changed Object to Map, alphabetic ordering fixes ,css changes in transcription subtitles

* Sends Map of transcriptMessages as prop to Component

* Documentation fixes and uses config in redux state

* Minor doc fix

* rename feature 'transcription' to 'subtitles'

* Moves subtitles config to interfaceConfig and minor fixes

* minor lint fix

Creating a new async prosody http wrapper.

feat(calls): Adding missed call event triggering.

* ref(device-selection): do not override var that is not reference again

* ref(device-selection): do not override var that is not reference again

* ref(device-selection): always update known devices on device list update

* ref(device-selection): replace call to get devices from legacy to redux

* ref(device-selection): remove unused device list state from mediaDeviceHelper

* ref(device-selection): update store before updating UI

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

It can be that deviceChangeListener is never defined because
the isDeviceList call never completes. On hangup, that would
cause an error to be thrown within lib-jitsi-meet because of
an attempt to remove an undefined event handler. That is
what happens on Safari right now.