- re-add thepand icon, shaped like a pill
- round top corners

Co-authored-by: DimaG <dgeorgiev06@gmail.com>

Moves NotificationContainer to the toolbox and filmstrip container, so
that there's no need to manually calculate the positions.

Turns out React Native offers an object with the following definition:

{
    bottom: 0,
    left: 0,
    position: 'absolute',
    right: 0,
    top: 0
}

- add 10px of padding on the sizes of the toolbar
- make the button margin smaller (from 10 to 7)
- increate the secondary button factor to 85%, thus rising the maximum secondary
  button size to 50 (from the previous 48)

- 5 buttons in the (now single) toolbar
- Overflow menu in the form of a BottomSheet
- Filmstrip on the right when in wide mode

Contributing all buttons in one place goes against the designs that we
set out at the beginning of the project's rewrite and that multiple of
us have been following since then.

Create standalone components for each feature and move all state to them.
Toolbars are now dummy containers.

With the introduction of wide and narrow layouts the margins of the
Filmstrip and the Toolbox became inconsistent. For example, the
Filmstrip's top in the wide layout was nearer to the top than the
secondary Toolbar.

Adds the ability to detect app area's aspect ratio on react-native
through the features/base/aspect-ratio.

Makes conference, filmstrip and toolbox react to the aspect ratio
changes and display filmstrip on the shorter side of the screen.

Match the one on the web.

The files styles.js are used (pretty much) on React Native only and each
of them exports 1 name. Export it as default to cut down on source code.

Remove toolbar button and icon style literals from the render method of
Toolbox.native.js.

Additionally, comply w/ coding style.

As an intermediate step on the path to merging jitsi-meet and
jitsi-meet-react, import the whole source code of jitsi-meet-react as it
stands at
2f23d98424
i.e. the lastest master at the time of this import. No modifications are
applied to the imported source code in order to preserve a complete
snapshot of it in the repository of jitsi-meet and, thus, facilitate
comparison later on. Consequently, the source code of jitsi-meet and/or
jitsi-meet-react may not work. For example, jitsi-meet's jshint may be
unable to parse jitsi-meet-react's source code.