mgr/dashboard: NFS exports: API + UI: integration with mgr/nfs; cleanups

mgr/dashboard: NFS exports: API + UI: integration with mgr/nfs; cleanups

mgr/dashboard: move NFS_GANESHA_SUPPORTED_FSALS to mgr_module.py

Importing from nfs module throws AttributeError because as a side effect the dashboard module is impersonating the nfs module.
https://gist.github.com/varshar16/61ac26426bbe5f5f562ebb14bcd0f548

mgr/dashboard: 'Create NFS export' form: list clusters from nfs module

mgr/dashboard: frontend+backend cleanups for NFS export

Removed all code and references related to daemons. UI cleanup and adopted unit-testing for
nfs-epxort create form for CEPHFS backend. Cleanup for export list/get/create/set/delete endpoints.

mgr/dashboard: rm set-ganesha ref + update docs

Remove existing set-ganesha-clusters-rados-pool-namespace references as
they are no longer required. Moreover, nfs doc in dashboard doc is
updated accordingly to the current nfs status.

mgr/dashboard: add nfs-export e2e test coverage

mgr/dashboard: 'Create NFS export' form: remove RGW user id field.

- Improve bucket typeahead behavior.
- Increase version for bucket list endpoint.
- Some refactoring.

mgr/dashboard: 'Create NFS export' form: allow RGW backend only when default realm is selected.

When RGW multisite is configured, the NFS module can only handle buckets in the default realm.

mgr/dashboard: 'Create service' form: fix NFS service creation.

After https://github.com/ceph/ceph/pull/42073, NFS pool and namespace are not customizable.

mgr/dashboard: 'Create NFS export' form: add bucket validation.

- Allow only existing buckets.
- Refactoring:
  - Moved bucket validator from bucket form to cd-validators.ts
  - Split bucket validator into 2: bucket name validator and bucket existence (that checks either existence or non-existence).

mgr/dashboard: 'Create NFS export' form: path validation refactor: allow only existing paths.

Fixes: https://tracker.ceph.com/issues/46493
Fixes: https://tracker.ceph.com/issues/51479
Signed-off-by: Alfonso Martínez <almartin@redhat.com>
Signed-off-by: Avan Thakkar <athakkar@redhat.com>
Signed-off-by: Pere Diaz Bou <pdiazbou@redhat.com>