Add skip-path Feature for Dependency Mirrors

[bitgully]

Summary

Adds skip-path feature for dependency mirrors.
This provides the option of skipping path segments of the original location as discussed here in regards to the /maven2 issue.

Usage: Can be used by a comma separated argument as in https://mirror.example.org,skip-path=/path-to-skip

Use Cases

1. Download all dependencies from https://mirror.example.org but skip /maven2 in the mirror's path if this is part of any original location.
   BP_DEPENDENCY_MIRROR=https://mirror.example.org,skip-path=/maven2

2. Download all dependencies from https://mirror.example.org using the original path but skip /maven2 on the mirror if the original path at https://repo1.maven.org includes this segment.
   BP_DEPENDENCY_MIRROR=https://mirror.example.org
   BP_DEPENDENCY_MIRROR_REPO1_MAVEN_ORG=https://mirror.example.org,skip-path=/maven2

This feature can also be used in dependency-mirror bindings.

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).

[dmikusa]

Thanks so much for this PR & sorry for the delay. It's looking good, just two minor things for your consideration.