issue DB schema statements each within savepoints

share/schema_versions/App-Netdisco-DB-52-53-PostgreSQL.sql

@@ -0,0 +1,13 @@
+BEGIN;
+
+ALTER TABLE netmap_positions DROP CONSTRAINT "netmap_positions_device_groups_vlan_key";
+
+ALTER TABLE netmap_positions RENAME COLUMN device_groups TO host_groups;
+
+ALTER TABLE netmap_positions ALTER COLUMN host_groups SET DEFAULT '{}';
+
+ALTER TABLE netmap_positions ADD COLUMN "device" inet;
+
+ALTER TABLE netmap_positions ADD COLUMN "locations" text[] DEFAULT '{}' NOT NULL;
+
+COMMIT;