Add local mode to commit linting script

Description

As a contribution to: gitlab-org/editor-extensions/meta#29, I've tried to add commit linting for local branches.

This involved:

• Adding a "local mode" to the existing script.
• Adding extra functionality to the existing script to work on local commits, rather than commits from an MR.

I noticed that one of the packages-lock.json files complained that it needed upgrading, so I regenerated it.

CC @aqualls @msedlakjakubowski @jglassman1

How has this been tested?

I ran lefthook run pre-push locally with conforming and non-conforming commit messages, and it seemed to work!

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap