feat: cleanup invalid symlinks in .local/state/mise/(tracked|trusted)-configs

[roele]

Fixes #2020 by introducing an experimental mise config prune command to prune invalid config file references from .local/state/mise/(tracked|trusted)-configs.

[jdx]

I think I'd prefer mise prune --config but I'm open to a reason why we would put it here instead

[roele]

This was my first thought as well but i would not like to prune any tools so it felt a bit weird to use an option and have to pass the additional --dry-run to ensure nothing else is pruned.

[jdx]

Ah yeah I did not think of that

[roele]

We probably also should also ensure in mise prune that both are cleaned up.

[jdx]

I'm not sure. I think there probably will be some small subset of users with directories that come and go which also use prune to clear out old tools—they may want references that don't exist

[roele]

Up until now, the tracked configs have been cleanup up as part of Tracker::list_all(). I moved that out to make it more explicit but we can skip the cleanup of those for prune completely.

[jdx]

Here's a thought, maybe we put everything under mise prune but if you specify --tools or --config that would filter so as to only prune that type. No args would essentially be like a (nonexistent) --all.

It might be worth looking at what docker system prune is doing for a potential reference.