mgr/dashboard: Adding group and pool name to service name

mgr/dashboard: Adding group and pool name to service name

- Pre-populating the service name field with the format `nvmeof.<pool_name>.<group_name>`.
- This can be changed by user but by default this value will be there.
- This will help user to quickly fill form and proceed hence improving usability.
- cephadm also uses this format as of now this convention so it will make UI aligned with CLI experience

- updates unit tests to improve coverage

- hides`count` values as that is not needed for 'nvmeof' only hosts and labels required.

Fixes https://tracker.ceph.com/issues/68065

Signed-off-by: Afreen Misbah <afreen23.git@gmail.com>
(cherry picked from commit e0e467a7a2011c991e487ab848750b59d79adc3f)