audio-only,lastn: move audio-only and last N handling to standalone features
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.
ref(video-quality): rename receiveVideoQuality to preferredReceiverVideoQuality
- "preferred" is being appended because in tile view there is a
concept of what the user prefers to be the maximum video quality
but there is also a maximum respected internall. For example,
the user may prefer HD, but in tile view the tiles may be small
so internall the preferred would be set to LD.
- "receive" is being renamed to "receiver" to be consistent with
the naming in lib-jitsi-meet.
Saúl Ibarra Corretgé
Bettenbuk Zoltan
Leonard Kim
Guus der Kinderen