WIP: remove the old database abstraction layer

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

while here:
- remove: TextStream, SLog, TexTextStream

winixd/core/groups.h

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2008-2018, Tomasz Sowa
+ * Copyright (c) 2008-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -39,7 +39,6 @@
 
 #include "models/group.h"
 #include "ugcontainer.h"
-#include "db/db.h"
 #include "winixmodeldeprecated.h"
 
 
@@ -64,7 +63,7 @@ public:
 
 	Groups();
 	void Clear();
-	void ReadGroups(Db * db);
+	void ReadGroups();
 	Group * GetGroup(long group_id);
 	Group * GetGroup(const std::wstring & name);
 	long GetGroupId(const std::wstring & name);