macosx: Auto-hide main library window toolbar during video playback

Part of a move to make video playback in macOS native full-screen window mode better

Enploys the same logic as the full screen playback controls, displaying on mouse movement and auto-hiding on inactivity

Screen_Recording_2022-12-07_at_21.25.01

Screen_Recording_2022-12-07_at_21.25.24

Signed-off-by: Claudio Cambra developer@claudiocambra.com