Add _get_module in DBResolver and fix _record_ursine_rpms
_record_ursine_rpms needs to get each collision module's koji_tag and
then get built RPMs from that koji_tag eventually. _get_module on each
individual resolver is called to get module metadata accordingly. So,
when running a local build, module metadata is got from remote MBS, and
for a MBS instance, connected database is queried.
Signed-off-by: Chenxiong Qi <cqi@redhat.com>