Add PostGIS GeoJSON support

Works for GET, POST, PATCH, PUT, DELETE, RPC.

test/spec/fixtures/privileges.sql

@@ -188,6 +188,8 @@ GRANT ALL ON TABLE
     , view_test
     , bulk_update_items
     , bulk_update_items_cpk
+    , shops
+    , shop_bles
 TO postgrest_test_anonymous;
 
 GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;