Grant postgres to awx user on migrate_data (#2038)

This is needed in case customers move to
operator platform.

Fixes https://issues.redhat.com/browse/AAP-41592

roles/installer/tasks/migrate_data.yml

@@ -77,7 +77,9 @@
       trap 'end_keepalive \"$keepalive_file\" \"$keepalive_pid\"' EXIT SIGINT SIGTERM
       echo keepalive_pid: $keepalive_pid
       set -e -o pipefail
+      psql -c 'GRANT postgres TO {{ awx_postgres_user }}'
       PGPASSWORD=\"$PGPASSWORD_OLD\" {{ pgdump }} | PGPASSWORD=\"$POSTGRES_PASSWORD\" {{ pg_restore }}
+      psql -c 'REVOKE postgres FROM {{ awx_postgres_user }}'
       set +e +o pipefail
       echo 'Successful'
       "