Add status bar

[Cretezy]

Add a status bar like Vim.

It should display the current change/commit (@), version, and more (ideas needed).

Pressing : should type in the status bar like Vim. r (revset input), / (search, in the future) should also be displayed here. A keybind to make the box multi-line would be useful for long commands.

This could also be used a progress bar for future background operations (push/fetch), or for future async architecture.