Conflicts:
- `.github/workflows/build-image.yml`:
Fix erroneous deletion in a previous merge.
- `Gemfile`:
Conflict caused by glitch-soc-only hCaptcha dependency
- `app/controllers/auth/sessions_controller.rb`:
Minor conflict due to glitch-soc's theming system.
- `app/controllers/filters_controller.rb`:
Minor conflict due to glitch-soc's theming system.
- `app/serializers/rest/status_serializer.rb`:
Minor conflict due to glitch-soc having an extra `local_only` property
- `GET /api/v1/admin/domain_allows` lists allowed domains
- `GET /api/v1/admin/domain_allows/:id` shows one by ID
- `DELETE /api/v1/admin/domain_allows/:id` deletes a given domain from the list
of allowed domains
- `POST /api/v1/admin/domain_allows` to allow a new domain:
if that domain is already allowed, the existing DomainAllow will be returned
