Tidying up cluttered TM views with sub-folders

[redwing]

1. Skins menu under View menu shows subfolders under MusicBee/Skins, but Theater Mode menu does not. This makes it inconvenient to look up lots of TM views under TheaterMode.List folder.

Proposal: If Theater Mode menu also shows subfolders, then users can organize their downloaded TM views by creating subfolders.

2. Now let's tidy up the cluttered embedded TM views.
MB has three drop-down lists for selecting them: tab, bottom pane, and modern compact player. But currently each list shows all TM views under TheaterMode.Embeded folder.

Proposal: If a user has "tab", "bottom", "compact" folder under TheaterMode.Embeded folder, let each drop-down list show TM views only under its own subfolder. And any TM views stored directly under TheaterMode.Embeded folder would show up in all the three lists. This way, non-forum members won't be affected by this change.