Upgrade typescript related packages
Fix new errors and warnings

feat(a11y): make (most) UI elements reachable via keyboard

Convert some files to TS
Move some styles from SCSS to JSS
Update design

Update title bar button: ParticipantsCountLabel -> SpeakerStatsLabel. Only show button when speaker stats is enabled
Add badge to the participants pane button to show participants count

Add new screen share layout with resizable top panel
Only enable new layout in large meetings (min 50 participants - configurable)

It's about to become very confusing, since we are going to add actual
local recordings with video.

This feature was never fully finalizeed since it required manual
processing of the files, as they were not uploaded anywhere.

In addition, unless one opens the local audio device without any audio
processing first, any tracks opened later will have audio proceessing
turned on, something not desirable for the scenario this feature was
designed for in the first place: podcasts.

This feature will likely come back as a JaaS demo / MVP where the local
recording is made outside of the Jitsi Meet iframe.

Updated animations
Added raised hands counter
Added max width to title bar