r578: initial server side implementation of samr_CreateUser(),

r578: initial server side implementation of samr_CreateUser(),
samr_CreateUser2(), samr_LookupNames(), samr_OpenUser(),
and samr_DeleteUser()

this uses a user template in the SAM db, of objectclass "userTemplate"
and dn CN=TemplateUser,CN=Templates,$BASEDN. Using a template allows
an admin to add any default user attributes that they might want to
the user template and all new users will receive those attributes.