Use XDG for history file

[luka-hash]

Add an option to first check for default cache directory (usually the one set with $XDG_CACHE_HOME). If it fails, it uses the file in users home directory.

More about XDG Base Directory Specification:

• https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
• https://xdgbasedirectoryspecification.com/

EDIT: Another option would be to check for $OAK_HOME variable, and use that.