[RN] Prevent multiplying remote thumbnails

With some of the preceding commits in the "multiplying remote
thumbnails" story line, I started hitting this error with 100%
reproducibility:

1. Have a remote participant prepared in conferenceA. Web will do as
well.
2. On iOS prepare to join conferenceB in Safari and use the same device
for step 3.
3. Join conferenceA on the iOS device from step 2 with audio-only. The
audio-only is so that avatars are always visible. Wait for the remote
participant prepared in step 1 to appear.
4. Switch to Safari and hit "Continue in the app" to have the app leave
conferenceA and join conferenceB.

What happens:
After the iOS device joins conferenceB in the Jitsi Meet app, the local
participant is on the large video (as expected) but the avatar of the
local participant is the default audo-generated auto-colored
placeholder. That's because this error was hit and the avatar couldn't
be "fetched".

The Jitsi Meet app always has at most 1 conference of primary interest.
It may have to juggle with 2 JitsiConference instances at the same time
if 1 is in the process of being left and one is joining/joined. But the
one which is joining or joined (which we call conference in the
features/base/conference redux state) is the one "of interest", the
other one is "clean up". Consequently, the remote participants of the
conference "of interest" are the remote participants "of interest" and
the others are "clean up". In order to reduce the time during which
there may be multiplying remote thumbnails, clean the remote
participants who are no longer "of interest" up.

"Middleware" redux state changes, not actions.

As part of the work on fixing the problem with the multiplying
thumbnails, we've associated remote participant w/ JitsiConference.
However, there are periods of time when multiple JitsiConferences are in
the redux state (and that period is going to be shorted by
StateListenerRegistry). In order to give more control to the feature
base/participants, reduce the occurrences of direct access to the
features/base/participants redux state and utilize the feature's
existing read access functions. Which will allow us in the future to
enhance these functions to access participants which are relevant to the
current conference of interest to the user only.

The commit message of "Associate remote participant w/ JitsiConference
(_JOINED)" explains the motivation for this commit.

Practically, _JOINED and _LEFT combined with "Remove remote participants
who are no longer of interest" should alleviate the problem with
multiplying remote participants to an acceptable level of annoyance.

Technically though, a remote participant cannot be identified by an ID
only. The ID is (somewhat) "unique" in the context of a single
JitsiConference instance. So in order to not have to scratch our heads
over an obscure corner, racing case, it's better to always identify
remote participants by the pair id-conference. Unfortunately, that's a
bit of a high order given the existing source code. So I've implemented
the cases which are the easiest so that new source code written with
participantUpdated is more likely to identify a remote participant with
the pair id-conference.

Additionally, the commit "Reduce direct read access to the
features/base/participants redux state" brings more control back to the
functions of the feature base/participants so that one day we can (if we
choose to) do something like, for example:

If getParticipants is called with a conference, it returns the
participants from features/base/participants who are associated with the
specified conference. If no conference is specified in the function
call, then default to the conference which is the primary focus of the
app at the time of the function call. Added to the above, this should
allow us to further reduce the cases in which we're identifying remote
participants by id only and get us even closer to a more "predictable"
behavior in corner, racing cases.

The commit message of "Associate remote participant w/ JitsiConference
(_JOINED)" explains the motivation for this commit.

The plan set in motion here is to associate remote participants with the
JitsiConference instances that created them in order to be able to
remove remote participants when a JitsiConference is no longer the
primary focus of the jitsi-meet app. And that's supposed to alleviate a
problem with multiplying remote thumbnails.

Doing all of the above in a single commit is a bit of a high order. So
I'm splitting the whole into multiple successive commits for the
purposes of observability, comprehension. Each commit is supposed to be
safe even if subsequent commits are not accepted, are reverted,
whatever. Obviously, without the successive commits, a commit may be
"unused".

One of the important pieces of the multiplying remote thumbnails "fix"
offered is removing remote participants who are no longer of interest
i.e. PARTICIPANT_LEFT. But in order for _LEFT to be implemented, _JOINED
must be implemented first.

[RN] Simplify absolute fill styles

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

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

[iOS] Fix running in Debug mode on a device

[RN] Toolbox disabled button styles

It allows for specifying an override style collection which is applied when the
button is disabled.

[RN] Toolbox toggled item labels

[RN] Dismiss OverflowMenu after selecting an option

* feat(toolbar): add beta tag to live streaming button

* tweak colors and border radius

Thsi fixed a regression in 8f75c2e279

The bundler script doesn't do anything (it literally exits right at the top)
when skipping the bundle. This is arguably wrong, because it doesn't generate
"ip.txt", the file with the bundler IP address either!

So, generate that ourselves. While ding this, also drop the need for xip.io,
which has also been removed from RN, since it gives more trouble than it solves.

Because a conference can fail before or after it's joined it must be
"left" in order to release any allocated resources like peerconnections,
tracks and all the other things.

Because there are multiple reasons on why a conference.leave() may fail
it's helpful to know if and why it happened.

Wait until the right button size has been calculated before rendering it.

Instead of using JS, just use CSS 100% width and height. This
also resolves a jitter that occurs on edge when a modal's
container appends to the body.

- 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)

Doing so in CONFERENCE_JOINED is too late because if we are moderators that
event will come first and we won't know what ID to match it with.

This is safe because our local ID is created early.

Show it if we are the only participant, and hide it the moment someone else
joins the conference.

It significantly speeds up debug builds, putting them on par with Android, where
we also don't bundle the React resources.

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

* fix(PresenceLabel): Use translated strings for the presence label.

* feat(sounds): Implements loop and stop functionality.

* feat(invite): Add ringtones.

* fix(invite): Code style issues.