* feat: use latest merge date/start date where available for availability text for schemes and locations
* feat: add tests for availability text
* feat: use startdate instead to track merges on schemes and locations
* feat: test startdates are set correctly on merged schemes and locations
* feat: add migration file
* feat: add scheme activating soon tests
* feat: add activating soon to scheme filtering
* feat: update scheme active_status
* feat: update tests
* refactor: lint
* feat: move merge orgs validation after orgs validation
* feat: update schema