WIP: remove the old database abstraction layer

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

while here:
- remove: TextStream, SLog, TexTextStream

winixd/core/plugin.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
@@ -99,7 +99,6 @@ struct PluginInfo
 	
 
 	// objects from winix which are accessible from a plugin
-	Db        * db;
 	Config    * config;
 	Cur       * cur;
 	System    * system;
@@ -208,7 +207,6 @@ public:
 	Plugin();
 	~Plugin();
 
-	void SetDb(Db * pdb);
 	void SetSystem(System * psystem);
 	void SetCur(Cur * cur);
 	void SetFunctions(Functions * pfunctions);
@@ -253,7 +251,6 @@ public:
 
 private:	
 
-	Db        * db;
 	Cur       * cur;
 	System    * system;
 	Functions * functions;