wslc support credential helpers

**Is your feature request related to a problem? Please describe.**
Some container registries can use short lived oauth tokens which are ideally provided through the use of credHelpers. For example in Google Cloud.

**Describe the solution you'd like**
Add support for configuring credHelpers, analogous to the `credHelpers` key in `~/.docker/config.json`

**Describe alternatives you've considered**
N/A

**Additional context**
https://docs.cloud.google.com/artifact-registry/docs/docker/authentication describes using https://github.com/GoogleCloudPlatform/docker-credential-gcr

Start by locating the WSL code and tests for wslc registry credential configuration; the issue does not name specific files or entry points. Compare the desired behavior with the `credHelpers` key in `~/.docker/config.json` and the linked `docker-credential-gcr` usage. Done means wslc can configure and use credential helpers for registries such as Google Artifact Registry.

Written by the indexing model from the issue text.