macosx: Enhance float on top
This MR:
- Adds a button to the main video view to trigger "float on top"
- Enables "float on top" windows to join other spaces, including full-screen ones, making it float on top of everything
Screen_Recording_2024-04-08_at_21.50.57
Signed-off-by: Claudio Cambra developer@claudiocambra.com