some refactoring for feature request [3453f314d]
  *  following the Liskov substitution principle, Execute/ExecuteFmt and protected EngineExecute() are defined for TSQLRest, replacing ExecuteAll()
  *  TSQLRestServerRemoteDB will now redirect into any TSQLRest instance
  *  renamed TSQLRestServerDB.InternalExecute() as explicit StoredProcExecute()