feature: Allow providing rc file

[mrexox]

Closes #185 #178 #99 #253 #249

⚡ Summary

• Add rc global option which allows to set the ENVs file

[PikachuEXE]

One issue
The generated code in hook looks like this

set -a
[ -f '~/.lefthookrc' ] && source '~/.lefthookrc'

However ~ would NOT be resolved to $HOME

I tested with more variants:

# works
[ -f "$HOME/.lefthookrc" ] && echo "$HOME/.lefthookrc exists"
# nope
[ -f '$HOME/.lefthookrc' ] && echo '$HOME/.lefthookrc exists'
[ -f '~/.lefthookrc' ] && echo '~/.lefthookrc exists'
# Original generated one
[ -f '~/.lefthookrc' ] && source '~/.lefthookrc'

My current workaround is to put absolute path in rc:

# See following doc for details
# https://github.com/evilmartians/lefthook/blob/master/docs/configuration.md#rc

# You can choose whatever name you want.
# You can share it between projects where you use lefthook.
# Make sure the path is absolute.
rc: /Users/username/.lefthookrc

If this would be fixed then the doc can remain unchanged
If not the doc should be updated to not use ~/.lefthookrc

[mrexox]

Hey @PikachuEXE! You are right, I missed that thing. Although I still feel like having able to set ~ or $HOME would be better, so I'll just remove quoting in a template.