[Linux] Use $XDG_DATA_HOME/joe instead of ~/.joe-data

[chocolateboy]

According to the XDG Base Directory Specification, user-specific data files files should be stored in $XDG_DATA_HOME/joe, or $HOME/.local/share/joe if $XDG_DATA_HOME is not defined.

There is a single base directory relative to which user-specific data files should be written. This directory is defined by the environment variable $XDG_DATA_HOME.

This avoids cluttering the home directory and simplifies including/excluding related directories from bulk operations such as backups.

Links

• XDG Base Directory support - Arch Wiki
• Equivalents of XDG_CONFIG_HOME and XDG_DATA_HOME on Mac OS X - Stack Overflow

Repos

• Wessie/appdirs
• cep21/xdgbasedir
• tajtiattila/basedir