Adds the pgmq extension to support queuing (#1120)
* add pgmq SQL only extension
* revert accidental file inclusion
* add public interface test coverage
* order by namespace for tables in interface test to make timescale stable since they use 3 schemas
* pgmq in prime
* update to pgmq 1.4.2
* regression tests for pgmq
* add pgmq migration test script
* add pg_partman
* remove pg_partman_bgq from test suite postgresql.conf
* checkin broken test
* checkin broken test 2
* bump pgmq to 1.4.4
* sync test outputs and pg_partman with 1.4.4
* add pgmq to supautils privileged extensions
