Implement tag use cases. Fixes T1079

Summary:
 - Add `DeleteTag` use case.
 - Add `UpdateTag` use case.
 - Add `ListTag` use case.
 - Add `AddTag` use case.

Test Plan:
Run
 - `./gradlew test`
 - See all test pass

Reviewers: dkobia, PapaLee

Subscribers: shadowhand, rjmackay

Maniphest Tasks: T1079

Differential Revision: https://phabricator.ushahidi.com/D485