Collection,Entity children funcs now use paging, don't store hits

- New function for getting all files in a Collection.
- .entities() and .files() functions now send paging args to
  DDR.elasticsearch.query().
- .entities() and .files() functions no longer store hits in the
  object, because the results may not include all the child
  objects, and also there may be too many for that to be practical.
collection.files, .entities; entity.files

NOTE: no paging yet.
collection breadcrumbs point to collections list instead of org

It was decided that rather than having separate repo and org pages
these would be conflated into a page that lists all orgs with their
collections.