Implements is_command_paper? and is_act_paper? on Attachment
Publication search_index includes has_command_paper / has_act_paper
Publications can be filtered by Official Document Status

Relies on change to rummager schema: https://github.com/alphagov/rummager/commit/8bb9977f98218b686fd7320c7836c1b784bcbfac
Move command/act paper methods into Publicationesque

Leaving tests in publication_test.rb until we decide on the best way to test the edition
family tree.
Document filter remove button has cursor

also removes unwanted class from mustache template for document filter.