Configure rails_admin to remove wasteful relations
Make outgoing email domain configurable
Fix language editing by emitting an enum for rails_admin
Filter on original_notice_id in rails_admin
Make more items practically editable via rails_admin
Quiet down the asset pipeline during dev
Fix numerous entity issues, including:

* Setting default columns to empty strings instead of null to avoid
  spurious indexing during notice edits.
* railsadmin interface
* Merge entities that're duplicates because of column value changes
Extract and test HierarchicalRelationships

Includes making them editable in rails_admin for Topics
Enforce available locales to silence deprecation warnings