Show a graphical breakdown of resources included in the search results

[jrdh]

This could perhaps be a tab all of its own and perhaps the default tab that users see when searching. It should at least show a graphical breakdown of where the records in the results have come from (this data is already available if when calling the datastore_multisearch action you pass top_resources: true) but could also show more. It could perhaps even work as more of a "dashboard" about the results, showing useful information whilst also providing links to the other tabs? Perhaps call it "Explore" or something.