Feature request: Use XDG_CONFIG_HOME directory to store configuration

[MichaelAkvo]

The script stores the configuration in the home directory, which clutters the directory. It would be great if it followed the Freedesktop spec

$XDG_CONFIG_HOME defines the base directory relative to which user-specific configuration files should be stored. If $XDG_CONFIG_HOME is either not set or empty, a default equal to $HOME/.config should be used.