Add data saver mode

[third774]

When enabled, this will stop pulling video tracks from other users—but only their webcams. Screensharing will still be pulled since it is more critical to understanding.

[danjenkins]

I'm not sure if you want to think about this here in this pull request or not but you say screen shares are more critical than webcams... but that's because you can hear.

Something I've been thinking about recently is accessibility for all and what that means in video calling apps. Data saving mode for a group of deaf people would be getting rid of the audio tracks if they're even sending any in the first place - in the grand scheme of things it's not a lot of data compared to video but it's still data.

Of course I say this as a non deaf person so I'm making assumptions

[third774]

Thank you! Very good call out, and my phrasing here definitely was not inclusive — sorry about that! We'd love to get live captioning built-in.

The thing we're looking to address with this right now is for users who have bad connections and are having a rough time when pulling 8 other webcam feeds during a meeting. Of course there are plenty of more robust ways of addressing this (simulcast, for one!), but we're making this available as a short term option.