Implement XDG compliance, logging, and improved 401 error handling

- Install to ~/.local/bin/winamp-mpris
- Use ~/.local/state/winamp-mpris/bridge.log for logging
- Use $XDG_RUNTIME_DIR/winamp-mpris.pid for PID management
- Add detailed user notification for 401 Unauthorized errors
- Add install.sh for automated, standard-compliant setup
- Include Winamp Web Interface source code and installer in repository

winamp-mpris.service

@@ -4,7 +4,7 @@ After=network.target
 
 [Service]
 Type=simple
-ExecStart=/usr/bin/python3 %h/Scripts/winamp-mpris/winamp_mpris.py
+ExecStart=%h/.local/bin/winamp-mpris
 Restart=always
 RestartSec=5