- Mono Layer release whith multi-stage building,

- Replace with label obsolete Maintainer command,
- Use .env file,
- Clean-up now uneeded sub dirs.

ReadMe.txt

@@ -8,7 +8,7 @@ Features:
     - Curtently based on official Mageia9 docker image from github.io,
     - Enable urpmi "Core", "Nonfree" and "Tainted" medium from "http://ftp.free.fr/" mirror,
     - Add Rx3 bash seting,
-    - Multi layered (Mageia + Rx3 Updates) + Mono (Merged)
+    - Mono layered (Mageia + Rx3 Updates)
 
 
 Enjoy it!