As it is now the controller DHCAP keys of hosts is set on the subsystem level. We want to allow setting it for a single host. To simplify things this should be mutually exclusive with subsystem keys. That is, if the subsystem has a DHCAHP key defined, we should fail setting a controller key for a host in this subsystem and if there is a host with a controller DHCAP key defined in a subsystem we shouldn't allow setting a key for the subsystem.
As it is now the controller DHCAP keys of hosts is set on the subsystem level. We want to allow setting it for a single host. To simplify things this should be mutually exclusive with subsystem keys. That is, if the subsystem has a DHCAHP key defined, we should fail setting a controller key for a host in this subsystem and if there is a host with a controller DHCAP key defined in a subsystem we shouldn't allow setting a key for the subsystem.