Fix paused view : fix the state display (next to username)and show username in remote view.
Add an API to get participant device count from the conference model.
Reduce mosaic max size before switchçng to lesser quality (9 to 6 participants).
Upgrade message banner to be more customizable on colors and icons.
Hide some buttons if the conference is not ready.
Fix title display if there is no elapsed time (remove the minus character).
Synchronize conferences list when new conference info is received (preparation work for remote concellation/edition).
Change color on exclusive buttons in conferences list.
Disable camera button on audio-only mode.
