[FEATURE] K9s inspired keymap

[greaka]

Is your feature request related to a problem? Please describe.
systemd-manager-tui looks similar to k9s, that's what made me install it too. When first starting it up, I automatically assumed that the keybinds are the same. They weren't and I pressed buttons that I didn't want to press.

Describe the solution you'd like
In case the keymap has no other tool that it likes to mimic, I want to propose having a look at how k9s behaves and implement a similar feel. It would be great to seemlessly switch between these tools.

Describe alternatives you've considered
I can get familiar with both tools, but accidentally killing apps is still possible when slipping up.

Additional context
https://k9scli.io/topics/commands/
https://github.com/derailed/k9s

Sadly there is no overview for all binds, you have to start the cli and attach to a local cluster to see them all.

[matheus-git]

It really would be good for TUIs to follow a standard, but suddenly changing the keymap can be bad for people who are already used to it. A runtime flag could be used to indicate a new keymap, but I don’t have plans to implement that right now. If anyone wants to open a PR, feel free.