mgr/dashboard: Custom Directive for verifying if user is read_only

mgr/dashboard: Custom Directive for verifying if user is read_only

This commit introduces two new Custom Directives: `FormInputDisableDirective` and `FormScopeDirective`.
By using the `cdFormScope` attribute of the directive we can customize the behaviour of the modal components.

Fixes: https://tracker.ceph.com/issues/43527
Signed-off-by: Nizamudeen <nia@redhat.com>
(cherry picked from commit f6e1ed657125e0f394e80da5dfeb51617304d091)

Conflicts:
      src/pybind/mgr/dashboard/frontend/src/app/shared/directives/directives.module.ts
 - Import the FormInputDisableDirective and FormScopeDirective to the directive.module imports and exports
      src/pybind/mgr/dashboard/frontend/src/app/shared/directives/form-input-disable.directive.spec.ts
 - Changed TestBed.inject(...) to TestBed.get(...) since in octopus the typescript version used is 3.5.3'
      src/pybind/mgr/dashboard/frontend/src/app/shared/directives/form-input-disable.directive.ts
 - Changed some of the operators to match the octopus TS version