Heat module doesn't work with the endpoint and database class structure

[michaeltchapman]

Since heat has a class for both the endpoint and the cfn endpoint, it needs to be treated differently if we are to add heat_cfn to enabled services and remove it from the class group.

We should add heat_cfn to enabled_services and include it via a special case, then delete it in coi::profiles::endpoints the way we do for swift in databases so it's not passed down to coi::endpoints.

Similarly we should delete it in the coi::profiles::databases class.