feed es view (bug 1036216)

Breaking https://github.com/mozilla/zamboni/pull/2298 up.

- Do a filter on FeedItem by region that puts matching region/carrier operator shelves on top.
- Do an OR query for FeedApp/Brand/Collection/Shelf using IDs
- Do an OR query for apps using IDs

Relies on [indexers](https://github.com/mozilla/zamboni/pull/2314) and [serializers](https://github.com/mozilla/zamboni/pull/2313).
Since region has a default now, you don't need the `if region`. I think this could be refactored a bit. E.g. you don't need a function score query if there's a region and not carrier since there's not function to apply -- it's just a simple filter. I'd imagine that's easier for ES to optimize.