Class for saved searches

I want to be able to create a series of saved searches, similar to how netflix works.

These could be:

1. a preset playlist (list of IDs) which retains order
2. A regular query, may need some ordering concept
3. A query with a bunch of facets pre-checked

Requirements:
1. When one of these is configured, it can be bound to some UI controls
2. When the UI controls are used (e.g. faceting) they can append to the saved search (not modify the original) so you can revert to the original
3. These should be serializable
4. There may need to be some UI control to 'revert' to the original

No files, tests, or entry points are named. Start by locating the existing search and UI-control entry points, then compare how preset playlists, regular queries, and faceted queries could be represented. Done means saved searches can bind to controls, serialize, append changes without mutating the original, and revert to it.

Written by the indexing model from the issue text.