When systemd is fully installed, `loginctl` does not support the actions
`reboot`, `poweroff` and `suspend`.
Fix this by using `systemctl` if installed.
Wrap lines at 80 columns where appropriate and I had the energy to think
about how/where to wrap.
There are still lines longer than that, which I plan to wrap in the
future. But that is enough for now.
Remove ": " from prompts since rofi adds them already.
Change order of yes and no when conforming so that <Enter> cannot
accidentally be pressed twice.
Use tabs instead of spaces.
Replace all occurrences of [ with [[ in bash and zsh scripts and
configs.
Performance wise it makes sense to use the builtin instead of calling an
external command also when from a functionality stand point `test` would
suffice.
