Allow associations to be completely generic.
Now the associations assume that they are account-entitlement or entitlement-entitlement relations. But we want account-account associations ... and maybe also generic-generic associations.
I have not foreseen the need for account-account association. As I'm thinking about it now there is nothing in the architecture that would prohibit that. But it is likely that the code is hardcoded in a way that the association target is an entitlement.