Follow Free Desktop Standards for config file

Like the vast majority of projects, you've opted to put a .rc file in the user `$HOME`. As much I understand how convenient it is (specially for app developers) I find really annoying to have hundreds of dotfiles in my home because I happened to use something one day.

Is there any possibility that you would migrate your configuration file to use the [Free Desktop Standard](https://specifications.freedesktop.org/basedir-spec/latest/index.html)?

This would mean using `$XDG_CONFIG_HOME/entropic`, defaulting to `$HOME/.config/entropic` if `$XDG_CONFIG_HOME` is not defined. Similar conventions could be followed for cached and application data.

If you think this is a good idea, I could volunteer for implementing it.

I understand this is may sound like a silly petition because is not a standard a lot of people is using nowadays, but I think you are in a position to set a nice example :)

PS: Sorry for ignoring the template, but I didn't know how to put this request in the provided fields.