DomainModelControllerService is installing the management request handlers for DC-related requests for slaves using cached-dc

The DomainModelControllerService code block that parses a local domain.xml is also installing the service the allows the management interface to accept requests that uses the request headers meant for the master side slave->master intra-domain communications. This service should not be added in the slave using cached-dc case, but it is now.

It also shouldn't be added if the DC is running admin-only.

OTOH in all cases where it is not added, a different service should be added that will reject any slave registration requests that come in with the correct error codes that the slave knows how to parse. Currently that rejection is only happening for admin-only masters or slaves that are using cached-dc, which is not correct.