mgr/cephadm: Expose nvmeof gateway configuration parameters through specifications

mgr/cephadm: Expose nvmeof gateway configuration parameters through specifications

- min_controller_id, max_controller_id: Enable the specification of minimum and maximum controller IDs utilized by the SPDK.
  Having distinct controller IDs is vital for configuring multipath setups.
- enable_spdk_discovery_controller: Manage whether the SPDK or ceph-nvmeof discovery service is employed. The default value is set to False.

Signed-off-by: Alexander Indenbaum <aindenba@redhat.com>