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).
In ES dsl:
```
from elasticsearch_dsl import filter
filters = []
for feed_item in feed_items:
    filters.append(F('term', id=feed_item[feed_item[['item_type']]))
    filters.append(F('term', item_type=feed_item['item_type']))

return filter.Bool(should=filters)
```