Added support for grouping tasks by challenge (#8469)

* Added support for grouping tasks by chllenge

* Fixed tests and updated default challenge model name

* Fixed broken member test

* Updated setting string

* Changed to shortName

* Began abstracting task grouping

* Added initial task directive code

* Added new directives to help with grouping of tasks

* Removed random console.log

test/api/v3/integration/challenges/POST-challenges_challengeId_leave.test.js

@@ -117,7 +117,9 @@ describe('POST /challenges/:challengeId/leave', () => {
       });
 
       expect(testTask).to.not.be.undefined;
-      expect(testTask.challenge).to.eql({});
+      expect(testTask.challenge).to.eql({
+        shortName: 'None',
+      });
     });
   });
 });