Adds the ability to filter Artefacts by owning application

* Refactors the exclusion of panopticon owned applications for easier testing
Consistent representation of Artefact application name
Merge pull request #175 from alphagov/filter-by-application

Adds the ability to filter Artefacts by owning application
Bump govuk_content_models to 12.2.0

We need this version to support manual-change-history artefacts from
specialist-publisher.
Merge pull request #179 from alphagov/support-manual-change-history

Bump govuk_content_models to 12.2.0