Add skip-path Feature for Dependency Mirror

[bitgully]

Summary

Adds the 'skip-path' feature for dependency mirrors.
This provides the option of skipping path segments of the original location as discussed here.

Use Cases

Identical to the cases mentioned in the related PR for libpak.

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).