CLI should respect user‘s XDG base directory settings

[yeskunall]

pscale shell creates a history file by default in $HOME/.pscale/history. While this is not an error, I think the CLI should respect an OS (or the user’s) XDG base directory settings. The history file should be placed under XDG_DATA_HOME: on Mac, it should go under ~/Library/Application \Support/.pscale and on most Unix-like operating systems, it should go under $HOME/.local/share.

I’d be happy to make a PR if you guys agree with the change.