pglogical: update to 1.2.0
pglogical-output: delete; merged into databases/pglogical

The databases/pglogical and databases/pglogical-output ports have been
merged into one codebase upstream, and database/pglogical now installs
the pglogical-output.so module.

pkg(8) should handle the merger correctly; portmaster(1),
portupgrade(1) users are advised to manually delete pglogical-output
before upgrading.