fix(config): add Windows home dir path

[Acamol]

On PowerShell / CMD the HOME environment variable is often not defined, so $HOME/.config/qbt will evaluate to C:/.config/qbt instead of C:/<username>/.config/qbt as one would expect.

[ludviglundgren]

Hey @Acamol , sorry for this taking so long to get back to. I made a change to use the built in filepath.join to build the path which should make it use the correct separator for the environment. On Windows that's backslash \.

Could you try this out and report back and if it's ok? Then we can merge this and get a new release out.

[Acamol]

It seems to be working fine on my system with your change.

[ludviglundgren]

Sorry about the delay, will get this merged and some other PRs and then make a new release :partying_face: