feat: use creds helper

[shaxbee]

Support pulling images from registries using docker credentials helper.
Backported auth related changes from go-dockerclient, when image is not found locally and image contains registry name credential helper will be called when available.

Checklist

• I have read the contributing guidelines
  and signed the CLA.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got green light (please contact
  security@ory.sh) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added necessary documentation within the code base (if
  appropriate).

[codecov]

Codecov Report

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The diff coverage is n/a.

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[shaxbee]

In order to write automated tests for this PR we would need private image and docker credentials helper provisioned in CI.
I tested it successfully with private images that we're using now :-)

[aeneasr]

Could you show a screen cast of this working with a private repo please? :)

[aeneasr]

ping @shaxbee please see above

[aeneasr]

While the PR is being worked on I will mark it as a draft. That declutters our review backlog :)

Once you're done with your changes and would like someone to review them, mark the PR as ready and request a review from one of the maintainers.

Thank you!

[tmc]

@shaxbee could you follow up here? This is a useful addition.

[vic3lord]

Any news regarding this one?