Add keybind to checkout commit in log view

[Omnikar]

This Pull Request fixes/closes #983.

It changes the following:

• Adds Shift-S keybind to checkout the selected commit in the log view.

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

I think it'd be better if I could add a confirmation before detaching HEAD, similar to the one used for branch deletion and such, but I'm not sure how to.

[Omnikar]

How do I get the keybind to appear in this bar at the bottom?

[extrawurst]

How do I get the keybind to appear in this bar at the bottom?

checkout the commands fn next to events to see how components add their commands

[extrawurst]

@Omnikar feel free to reach out on our discord aswell

[extrawurst]

@Omnikar are you planning to follow this up?

[fralcow]

Hey @extrawurst , I'm willing to pick this issue up. I see you left a couple of comments to the original author regarding unit tests and code reuse, should I pick up their branch and fix this stuff, or would you suggest rewriting the whole thing from scratch?