WIP: remove the old database abstraction layer

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

while here:
- remove: TextStream, SLog, TexTextStream

winixd/core/system.h

@@ -5,7 +5,7 @@
  */
 
 /* 
- * Copyright (c) 2010-2022, Tomasz Sowa
+ * Copyright (c) 2010-2024, Tomasz Sowa
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -39,7 +39,6 @@
 #include "job.h"
 #include "dirs.h"
 #include "mounts.h"
-#include "db/db.h"
 #include "request.h"
 #include "config.h"
 #include "crypt.h"
@@ -116,7 +115,6 @@ public:
 
 	void SetCur(Cur * pcur);
 	//void SetConfig(Config * pconfig);
-	void SetDb(Db * pdb);
 	//void SetSynchro(Synchro * psynchro);
 	void SetFunctions(Functions * pfunctions);
 	void SetSessionManager(SessionManager * sm);
@@ -229,7 +227,6 @@ public:
 private:
 	
 	Cur     * cur;
-	Db      * db;
 	//Config  * config;
 	//Synchro * synchro;
 	Functions * functions;