Pass the FS to k6deps

[pablochacin]

What?

Creates a bridge between the internally used afero.Fs library and golang's standard fs.FS and use it in the k6deps library.

Why?

afero.FS will eventually be removed from k6. Therefore, we want to prevent creating more dependencies from this library

Checklist

• [ ] I have performed a self-review of my code.
• [ ] I have commented on my code, particularly in hard-to-understand areas.
• [ ] I have added tests for my changes.
• [ ] I have run linter and tests locally (make check) and all pass.

Checklist: Documentation (only for k6 maintainers and if relevant)

Please do not merge this PR until the following items are filled out.

• [ ] I have added the correct milestone and labels to the PR.
• [ ] I have updated the release notes: link
• [ ] I have updated or added an issue to the k6-documentation: grafana/k6-docs#NUMBER if applicable
• [ ] I have updated or added an issue to the TypeScript definitions: grafana/k6-DefinitelyTyped#NUMBER if applicable

Related PR(s)/Issue(s)

Requires https://github.com/grafana/k6deps/pull/113