Display current repository path in the top-right corner

[alexmaco]

This Pull Request fixes #1341.

It changes the following:

• displays current repository path in the top-right corner

I followed the checklist:

• [ ] I added unittests
• [x] I ran make check without errors
• [x] I tested the overall application
• [x] I added an appropriate item to the changelog

[extrawurst]

nice one to tackle. but maybe we can find a better way to cut/shorten the path if the terminal size is very small:

maybe it should be something like: [..]ephan/code/gitui/

[extrawurst]

can you update and cleanup the conflicts?

[extrawurst]

Thank you!