[tvOS] ItemTypeLibraryViewModel - Implement FilterViewModel

[JPKribs]

Summary

I'm trying to get in the habit of doing more manageable / single item PRs. This one is the last step for #1407 before we start needing to have UI discussions.

This PR changes the ItemTypeLibraryViewModel and PagingViewModel. The primary change is the init for ItemTypeLibraryViewModel that accepts ItemFilterCollection as a parameter. This replaces the existing init and results in ItemTypeLibraryViewModel having a FilterViewModel. This enables the ability to perform filtering on the generic Shows / Movies.

I've tested this implementation works via #1407. I am splitting this out so we can get all the groundwork for filtering done now so we can hit the ground running when we have a plan for what we want that to look like. Additionally, this lets us confirm this implementation is done in the cleanest fashion possible without the clutter of other filtering components at the same time.

[LePips]

It's been a while since I've looked at these and realize there is potential for a good amount of cleanup, like removing ItemTypeLibraryViewModel entirely, and some API improvements. I've added those comments.