Add heimdall container image to ghcr.io repository

[dadrus]

Preflight checklist

• I agree to follow this project's Code of Conduct.
• I have read and am following this repository's Contribution Guidelines."
• I have discussed this feature request with the community.

Describe the background of your feature request

DockerHub introduced rate limites back in 2020, which can become annoying especially in free tier.

Describe your idea

Publish the heimdall container images in ghcr.io in addition to DockerHub.

Are there any workarounds or alternatives?

There are also repositories from AWS and Google Cloud. These are however not available in free tier.

Version

v0.11.1-alpha

Additional Context

No response