feat(config): look up from .config subdir by default, too

[scop]

Closes # (issue)

⚡ Summary

Look up configs from .config subdirs too, to help unclutter project top level dirs, https://github.com/pi0/config-dir (and other similar proposals)

pi0/config-dir support discussion item: pi0/config-dir#6 (comment)

This is a draft for discussion purposes, to be still done at least

• tests
• the .config/lefthook and .config/lefthook-local source dirs should work out of the box, too
• decide how relative paths should work and make sure they do that way, e.g. should they always be from the "top level dir" no matter if the config is in .config, or relative to that dir (I think I'd propose the former)
• remove with uninstall

☑️ Checklist

• Check locally
• Add tests
• Add documentation

[mrexox]

Hey! This sounds good! Could you also add the paths to uninstall?

I don't think moving scripts to .config/ is a good idea, since scripts are not configs actually, they must belong to repo root.

Regarding the paths I think it's better consider lefthook as being run from git project root always, for simplicity. So moving a file from repo root to .config/ doesn't make you change the config adding ../ to the root option, etc.