Add support for screen sharing

[ekrekeler]

Currently it seems like there is no support for screen sharing in a voice chat. This is the one thing that is keeping me from migrating away from Discord.

Are there any plans to incorporate this in a future release?

[insertish]

It is planned but it may take a while before it ends up being implemented.

[nerrixde]

revoltchat/vortex#9 is in "done", while it's not done just closed bc dupe

[insertish]

Removing issues so they can be reorganised when this project is ready to go ahead again, https://github.com/revoltchat/backend/issues/313.