Add support for credential helper to authenticate against the upstream registry

[dimitar-kostadinov]

How to categorize this issue?

/area security
/kind enhancement

What would you like to be added:

Evaluate this PR and provide a way to configure a credential helper for upstream authentication.

Why is this needed:

If AWS ECR credential helper can be configured, it could potentially resolve this issue.

[gardener-ci-robot]

The Gardener project currently lacks enough active contributors to adequately respond to all issues.
This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle stale
• Mark this issue as rotten with /lifecycle rotten
• Close this issue with /close

/lifecycle stale

[ialidzhikov]

/remove-lifecycle stale

[Noamrok]

Hi,
This feature will be a huge help for us.
Any plan to move forward with this?