Revert "Pass HTTP error code further to the client"

This reverts commit 997115e3cefdfc02f46b391cd6a353a0c70c7f8a.
Change the default "solr_select_url" to an array because that's how it's defined in the example in mediawords.yml.dist
Make MediaWords::Solr::query_encoded_json() support an optional $c (Catalyst context) parameter through which the subroutine will set HTTP status codes for failed Solr requests