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.

i18next.options are initialized before interfaceConfig overwrites are processed which leads to wrong translations.

* ref(feedback): emit api feedback submitted on completion

Compared to firing the event on submission because
the submission ajax will not be completed at that
time..

* squash: update package.json

The filmstrip is currently only hidden when PiP mode is entered. There is no
real reason not to leave the large view as it was.

When a participant is pinned in the UI we then proceed to mark it as selected on
the JVB. This will make the participant part of the last N set and will receive
the highest (or configured highest) video quality.

Pinning a participant at the JVB level just makes sure it will be part of the
last N set.

Since only one participant can be pinned in the UI, there is no point in pinning
it at the JVB level, since selecting it already achieved the same result.

Bumps LJM to 3c80587431.

Moves getCurrentConferenceUrl method to base/connection to allow reuse.
The new location is not ideal, but looks the best based on the imports
required (trying to avoid circular dependencies).

Support for the MediaStream constructor has been added to react-native-webrtc.

It was added for
3ea2f00578
over 2 years ago. That's long enough!

* Moves talk while muted as a new feature.

* Adds sound notification for talk while muted.

* Reorder imports and changes the dispatch of the notification.

* Introduces sounds.js for talk while muted.

This maps the tow letter languages as enGB to the country file for en.
Copies countries-en.json as countries-enGB.json.