Allow for overloading usecases for specific resource actions, refs T696

Test Plan:
```
bin/behat -f progress -c application/tests/behat.yml application/tests/features/api.tags.feature
```

Reviewers: rjmackay

Reviewed By: rjmackay

Subscribers: srutto, aMoniker, vladimir

Maniphest Tasks: T696

Differential Revision: https://phabricator.ushahidi.com/D403