Support minimizing to system tray

[DeSu0556]

#89 Support minimizing to the system tray, from which you can then reopen the ui

[DeSu0556]

Im really sorry. idea has initialized some code, which may cause the submission to be a bit messy.

[RoanH]

Hello, thank you for your contribution!

In general I think the implementation looks fine. It probably makes sense though to tie tray minimisation into the already existing command to hide the application (Ctrl + Y). I'm currently busy rewriting most of the internal logic to reduce the amount of technical debt in the project. After I'm done with that I'll get to this PR and then it'll most likely be included with the next release (towards the end of this week hopefully).

[RoanH]

I made some minor changes and tied the logic into the existing command to hide the application. If you're fine with those changes then I'll merge this.

Thanks again for the contribution! This is a really cool feature to have ^_^

[DeSu0556]

I am also very honored to contribute to KPS! If I can help with other issues, I will do my best to help.

[RoanH]

Awesome! You can find more open issues here if you want, though new ideas are also welcome of course.