Alternative desktop sharing (RTMP?)

**Is your feature request related to a problem? Please describe.**
Yes. Screen sharing via browser, especially if sharing games, can be taxing on a machine and downright unusable in the game case.

**Describe the solution you'd like**
Exposing something that would let us use an external capturing software like OBS, for example via an RTMP endpoint.

**Describe alternatives you've considered**
* Developing a high performance capture helper module / injectable. (too much work)
* Using a video camera feed as screen sharing source, and using the OBS virtual camera output. (this currently "works", but has terrible quality and the screen is mirrored)

**Additional context**
Other chat platforms like Discord solve this by having an hook dll that captures game data for full screen games, or using various other high performance apis for full screen non-game capture.