Boost collection-level results

[anarchivist]

Collection-level results don't appear first; e.g. Ed Feigenbaum papers should appear for a search for feigenbaum.

From estimation discussion:

• This may be ameliorated by grouping search results by collection.
• Is this overly prescriptive?

[ggeisler]

Issue #369 includes a design mockup that provides two views of the search results: one view is what we have now (all matching components sorted by relevance by default), and another view that groups results by collection.

We didn't implement that second view in the previous workcycle, likely due to lack of time, but from the comments in the issue it seems like it would take work but is technically feasible.

Would adding the Group by collection view to search results as shown in #369 address the concerns that prompted the creation of this ticket?

Or, maybe the solution is two-part, with both UI and indexing components:

• Implement the Group by collection view recommended in #369
• Refine the Solr config or other indexing-related things to improve the relevance-ranking of results.