Add sorting support at parser level using traits, refs T669

Summary:
- add new traits for parsing sorting: VerifiedParser, SortingParser, and SortableData
- use new traits for tag searches
- use new traits for paging parameters

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

Reviewers: eyedol, rjmackay

Reviewed By: rjmackay

Subscribers: srutto, dkobia, bodacea

Maniphest Tasks: T669

Differential Revision: https://phabricator.ushahidi.com/D293