Mobile devices do not support capture from multiple cameras/mics at a time.

When on prejoin screen, if the device list changes (devices are added or removed),
the newly created tracks do not properly replace the old ones, resulting in
errors after joining the meeting and trying to change the devices.
This change fixes the problem.

Android for Enterprise provides special feature for applications to obtain configuration through RestrictionManager remotely by some MDM solution.

Jitsi Meet can be remotely installed and provisioned with a proper URL (making URL not editable by the user) inside the Work Profile or Fully managed device.

- Disables the invite buttons while invites are ongoing
- Adds a keyboard shortcut (Enter) to send out invites
- Closes AddPeopleDialog upon successful invites sent
- Fixes the SecurityDialog closing when trying to set E2EE key via Enter shortcut
- Removes superfluous separator from SecurityDialog

Fixes #7093.

720 is requested by default for the local video stream
and when using the quality slider the resolution would
be increased to 1080.

Note that this will limit the receive quality to 720 as well,
because both send and receive constraints are changed at
the same time when the quality slider is used.

- Remove external install dialogs and fix related screensharing error handling.
- Remove obsolete options from config.js and from configWhitelist.js

saghul: torture tests also need it.

When setSubject is called too early we store it as pensing, but thanks to the
default parameter value, if undefined is passed to the function we'll store the
empty string.

This will trigger a needless update because undefined !== ''.

Skip processing any other participant updates.

Fixes: https://github.com/jitsi/jitsi-meet/issues/5673

Fixes: https://github.com/jitsi/jitsi-meet/issues/5673

There are occasions when role to moderator can change a little bit after joining the room, and initial try to set subject will silently be ignored if not moderator.

Up until now we relied on implicit loading of middlewares and reducers, through
having imports in each feature's index.js.

This leads to many complex import cycles which result in (sometimes) hard to fix
bugs in addition to (often) breaking mobile because a web-only feature gets
imported on mobile too, thanks to the implicit loading.

This PR changes that to make the process explicit. Both middlewares and reducers
are imported in a single place, the app entrypoint. They have been divided into
3 categories: any, web and native, which represent each of the platforms
  respectively.

Ideally no feature should have an index.js exporting actions, action types and
components, but that's a larger ordeal, so this is just the first step in
getting there. In order to both set example and avoid large cycles the app
feature has been refactored to not have an idex.js itself.

> playinline attr needs to be set to true to stop local video from playing in full screen mode in Safari on iOS.
> This applies to the local video thumbnails and the camera previews from the device selection menu and video preview button

The lobby feature adds the possibility to lock a meeting and only allow people in after virtually knocking and going through formal approval