We are moving away from using OpenSearch and depending on the Publish
app to get search results and information about datasets. We can use
the RSolr gem to query for this information directly from Solr.

This allows us to perform a basic query to Solr which will return a
maximum of 20 datasets if they are available. We specify the fields
to be included in the response which will then be available to use
in the view.

The default behaviour for this page is to show all results if a search
term has not been provided. This initial search page does not have
working filters or a working search box, and the results do not link
to individual dataset pages. Their functionality will be added in
future commits.

We still want OpenSearch to be our default search method, but we can
access the alternative search using Solr via /search/solr.