WIP: remove the old database abstraction layer

remove such classes:
- DbBase
- DbConn
- DbTextStream
- Db

while here:
- remove: TextStream, SLog, TexTextStream

winixd/core/request.h

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2008-2023, Tomasz Sowa
+ * Copyright (c) 2008-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -42,7 +42,6 @@
 #include "models/item.h"
 #include "error.h"
 #include "config.h"
-#include "textstream.h"
 #include "templates/htmltextstream.h"
 #include "date/date.h"
 #include "space/space.h"