winbindd: rework add_trusted_domain(), replacing add_trusted_domain_from_tdc()
This extends add_trusted_domain() to be a the one true one-stop function
to add winbindd domain.
add_trusted_domain_from_tdc() used a struct winbindd_tdc_domain to fill
in the winbindd domain which made it hard to track which attributes
would be required and which are optional.
Pair-programmed-with: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Ralph Boehme <slow@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>