Improved CRUDController tests and doc blocks

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT

*  Added CSRF token tests in CRUDController
* Improved isGranted test in createAction
* Improved doc blocks in CRUDController
Code coverage of CRUDController: 98.08% (96.71% before this PR)