We don't renegotiate down connections yet, but this is a latent bug.

If autoplay is not working on browser, user can play the video with this button

Reorganize radio buttons also.

No UI for now.

These functions require having joined a group, not just having
proper credentials.

Thanks to Antonin Décimo.

Co-authored-by: Juliusz Chroboczek <jch@irif.fr>

Reduce button size and reduce video control bar size.
Add a volume slider to control volume level when volume control is enabled

There is no text on mobile layout

This was causing us to lose connections.

This simplifies the interface since close does the right thing
without help from the application.  Also improves error checking.

We now treat local and remote candidates differently, and flush
local candidates immediately after sending an offer.