[IMP] Allow reviewers to accept/reject abstracts

 - Implemented functionality to allow the reviewers to accept and reject directly the abstracts
 - Used the same template as for the manager part
 - Create RH with all the functionality to accept and reject
 - Included new attribute in AbstractReviewing to register if the reviewers can accept/reject abstracts directly
[FIX] Post commit fixes

- Changed the red/green square to a remote checkbox
- Some code refactor
- Deleted obsolete code.
- See #330.