RSpec support files for cleaning Fedora and Solr

[alepbloyd]

In RSpec testing, we need to clear:

• The test database
• The /test base path for fedora
• The scholarspace_test solr core.

For convenience, we have a support file doing this for the test database (https://github.com/gwu-libraries/scholarspace-hyrax/blob/master/spec/support/database_cleaner.rb) and should set up similar support files for cleaning Fedora with ActiveFedora::Cleaner.clean! and Solr with:

let(:solr) { Blacklight.default_index.connection }
solr.delete_by_query("*:*")
solr.commit

Or a similar setup.