macosx: Make the playlist accessible when using the video view in the main library window

This MR changes the video view's behaviour to make it a part of the library target view, rather than have it overlap all the internal contents of the main library window. This makes the playlist accessible while a video is playing.

Video of the changes (note: contains fixes from !2782 (merged))

Screen_Recording_2022-11-04_at_01.39.40 Screen_Recording_2022-11-04_at_01.41.14

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