Callview: new layout button

Goal

The goal is to start to implement what is in the screenshot.

The 7 first options are possible to implement.

• Move fullscreen in this menu

• Move the Mosaic button inside this menu

• Ability to hide self (should be saved as a preferences of the app)

• Move the small pictures when somebody is on stage on one side (should be saved as a preferences of the app)

• Show participants without video or not (should be saved as a preferences of the app)