upgrade: fix config of sidgen and extdom plugins
During upgrade to IPA 4.2, literally "$SUFFIX" value was added to
configuration of sidgen and extdom plugins. This cause that SID are not properly configured.
Upgrade must fix "$SUFFIX" to reals suffix DN, and run sidgen task
against IPA domain (if exists).
All trusts added when plugins configuration was broken must be re-added.
Reviewed-By: Tomas Babej <firstname.lastname@example.org>
Reviewed-By: Alexander Bokovoy <email@example.com>