add test docker image to ghcr for dynamic VM testing

[gdams]

The Docker image is loosely based off the dockerStatic Dockerfile that we've been deploying to this point. This image will be consumed by dynamic test agents as part of adoptium/aqa-tests#5683

We can add more base images as appropriate but I thought I'd keep it simple for now

Checklist

• commit message has one of the standard prefixes
• faq.md updated if appropriate
• other documentation is changed or added (if applicable)
• playbook changes run through VPC or QPC (if you have access)
• VPC/QPC not applicable for this PR
• for inventory.yml changes, bastillion/nagios/jenkins updated accordingly

[github-actions]

A block has been put on this Pull Request as this repository is temporarily under a code freeze due to an ongoing release cycle.

If this pull request needs to be merged during the release cycle then please comment /merge and a PMC member will be able to remove the block.

If the code freeze is over you can remove this block by commenting /thaw.

[gdams]

/thaw

Pull Request unblocked - code freeze is over.

[sxa]

The Docker image is loosely based off the dockerStatic Dockerfile that we've been deploying to this point.

I think we should try and avoid having more sets of dockerfiles that we're using at the project as it just becomes harder to maintain. I'm unclear why we've made so many changes relative to the current one in the DockerStatic role. The primary change seems to have been to remove the jenkins user ssh key related stuff, but if that doesn't actively cause a problem I would suggest we leave it in for now and just use the original. If we really need to have differences then perhaps we can parameterise, or if needed grep out other lines.
This new dockerfile also seems to have removed required packages such as fakeroot from the files so is already diverging and creating maintenance concerns.