Add Delete Usecase. Fixes T820

Summary:
  - Add Delete usecase interface.
  - Implement the Delete usecase.
  - Define test cases for the Delete usecase
Initial implementation of delete use case

Test Plan:
  - Run ./gradlew test

Reviewers: dkobia

Subscribers: shadowhand, rjmackay

Maniphest Tasks: T820

Differential Revision: https://phabricator.ushahidi.com/D370