Adding missing 'regionextra' table and associated handlers to the PgSQL adapter.

Signed-off-by: UbitUmarov <ajlduarte@sapo.pt>

OpenSim/Data/PGSQL/Resources/RegionStore.migrations

@@ -1293,3 +1293,14 @@ ALTER TABLE spawn_points DROP CONSTRAINT spawn_points_pkey;
 ALTER TABLE spawn_points ADD CONSTRAINT spawn_points_pkey
     PRIMARY KEY ("RegionUUID", "Yaw", "Pitch", "Distance");
 COMMIT;
+
+:VERSION 57         #----- Adding a table missing from the PgSQL adapter
+BEGIN;
+CREATE TABLE "regionextra"
+    (
+        "RegionID" char(36),
+        "Name" varchar(32),
+        "value" text,
+        PRIMARY KEY ("RegionID", "Name")
+    );
+COMMIT;