Upgrade AuthUserRequest ref-counting

Upgrade AuthUserRequest ref-counting

TODO:
 Test auth still runs. Some problems were noted in conversion which affect
digest, NTLM, Negotiate AuthUser objects.
Notably that the virtual functions setting a custom field instead of the
parent objects _auth_user woudl result in teh *::Pointer having a NULL user()

 Convert AuthUser, AuthScheme, AuthConfig to ref-counted as well.