FEATURE REQUEST: [PLM] Various Functionality Updates

[babsonnexus]

(1) Be able to turn off an individual Parent station, similar to source Playlists.

(2) Be able to override the 'Stream Format' of a child station. This will allow, for instance, setting an individual station from a source Playlist set as HLS to be MPEG-TS.

(3) In 'Modify Assigned Stations' and 'Unassiged Stations', remove the 'Choice 2' column (Make Parent) because the function is redundant now and real estate will be needed for item 2 above. This will also mean changing 'Choice 1' to just 'Action' and making that action be 'Save Individual'.

(4) Add 'filter' memory. In other words, if a list is filtered, upon save that input should be remembered and put back so it is not forgotten and brings the user back somewhat where they were. This is a stepping stone to the possibility of being able to address Issue #14.

(5) Expand 'Streaming Stations' capabilities to other sources, like Twitch. This is actually ready to go, but just listing here as part of this package of updates.

(6) Create a web player for previewing stations and videos. This will assist in testing, be useful for #36, and will help make #26 possible.

(7) Make PLM on by default as it is mature and one of the major reasons for installation. This will make each extension on by default and able to be turned off by the user.

(8) Also make Streaming Stations on by default for the same reason. There is a tighter integration for everything that is coming.

(9) All of this will necessitate a fair amount of documentation updates.