Full Plex search

[chrisbenincasa]

Flesh out Plex search, right now we just support title prefix. There's a lot more...
https://github.com/pkkid/python-plexapi/blob/abcab4f78d22e86b380327c6014d3148e0248e6d/plexapi/library.py#L1282-L1535
shows a piece of what is possible.

Some thoughts:

• Look into how to dynamically derive the different tags available - this powers the dropdowns that control tag value to search on and operator
• Is caching an option? Unclear how hard this is on the Plex server
• Maybe we can start with a well-defined subset of fields -- title, year, genre, etc.

[chrisbenincasa]

Also just to note this work will serve as the basis for one of the ways to build dynamic channels