- opens as a modal
- lastn is 0, mutes local video while open
- long press to talk
- and more

* fix(multi-stream) update selector to find ss track by videoType or mediaType

* ref(multi-stream) move fake ss creation logic and support video type changed

* refactor(multi-stream) decouple sending and receiving multiple screenshare streams

* fix(multi-stream) fix receiver constraints with signaling and without multi-stream

* fix(mutli-stream) ensure plan b original SS thumbnail displays avatar

* fix(multi-stream) show fake SS for plan b sender

* refactor(multi-stream) poc for moving SS creation to state listener

* remove reference to fake SS creation

* fix lint errors

* rename to virtual screenshare participants

* fix minor bugs

* rename participant subscriber to specify web support only

If last N goes down to 1 it will be stuck there since it's > 0 and will
be our `lastNSelected`. When limits are applied we'll take the minimum,
so it will end up being 1.

Once can end up in last N being 1 by several means, the more obvious one
by entering Picture-in-Picture mode on mobile.

Fix it by not using the previous last N value for the current
calculation, at all.

Fixes: https://github.com/jitsi/jitsi-meet/issues/10257
Closes: https://github.com/jitsi/jitsi-meet/pull/10491

prioritize participants with screen shares
support local screen share track
auto pin screen share
support screen share for large video
ensure fake screen share participants are sorted
fix local screen share in vertical filmstrip
fix local screen share in tile mode
use FakeScreenShareParticipant component for screen share thumbnails
ensure changes are behind feature flag and update jsdocs
fix bug where local screen share was not rendering
update receiver constraints to include SS source names
remove fake ss participant creation on track update
fix: handle screenshare muted change and track removal
refactor: update key values for sortedFakeScreenShareParticipants
address PR comments
refactor getter for screenshare tracks
rename state to sortedRemoteFakeScreenShareParticipants

The receiver video constraints that are actually sent to the bridge are logged in LJM and need not be logged in the application.

When joining a large meeting every participant join would trigger an attempt of
an update. Try to minimize the amount of calls.

The client now listens for changes to lastN, selectedEndpoints and maxReceiverVideoQuality in redux to trigger sending  bridge message in the new format. This fixes an issue where the stage view <-> tile view changes prompt two receiver constraints messages to be sent, first with the maxHeight update and then with the selected endpoints update.

If limitLastN values are specified and channelLastN < limitLastN, configure channelLastN on the conference.

Co-authored-by: Saúl Ibarra Corretgé <saghul@jitsi.org>
Co-authored-by: zycwind <391321232@qq.com>

This fixes an issue where lastN is not bumped to 1 on an audio-only client when a screenshare source is added to the call.

Adds 'lastNLimits' config value which allows to define last N value per number of participants.
See config.js for more details.

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.

React Native doesn't define __filename nor __dirname so do it artisanally. In
addition, this helps with centralizing the configuration passed to loggers.

It's an evolution of audio-only mode, where we also allow for receiving a remote
screen-share.

Diving deeper: this basically sets last N to 1 or 0 depending on the
availability of a screen-share.

This refactors all handling of audio-only and last N to 2 features in preparation
for "low bandwidth mode".

The main motivation to do this is that lastN is a "global" setting so it helps
to have all processing for it in a single place.