WIP: remove the old database abstraction layer

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

while here:
- remove: TextStream, SLog, TexTextStream

winixd/functions/functionparser.h

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2008-2022, Tomasz Sowa
+ * Copyright (c) 2008-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -38,7 +38,6 @@
 #include <string>
 
 #include "core/winixmodeldeprecated.h"
-#include "db/db.h"
 #include "core/cur.h"
 #include "core/dirs.h"