Feature for focusing to a specific user in the video room.

### Your use case

#### What would you like to do?
1. It would be great if we could be able to set specific user to focus on for the spotlight layout instead of jumping between active(speaking) users.
2. If there is an option to make the spotlight to be displayed in full-screen (both mobile & desktop) that would be nice.
3. If there was an option to hide non-camera users from the video chat, that would also be great.
4. If one can adjust the layout of cameras (size, aspect and position) that can be useful.

#### Why would you like to do it?
I am trying to migrate from discord to matrix + element, and these features are very often used by me and my group when using discord. The features 1 to 3 are already in Discord.
Thanks!

#### How would you like to achieve it?

### Have you considered any alternatives?

_No response_

### Additional context

_No response_