Add create/init repository to main

[WTFive]

I know it's a small thing, but it would be great if you could add a new repository initialization function to the main window. I apologize in advance if such functionality exists, but I couldn't find it.

[love-linger]

You can open a folder from Repositories page. If it is not a valid git repository, the Initialize Repository dialog will popups.

[WTFive]

I didn't check the most obvious thing, sorry for wasting your time(