Sync ci images to dockerhub and ecr

What does this MR do?

Syncs images published to GitLab registry to ECR and DockerHub using skopeo.

I had to resort to using skopeo since maintaining and straight up getting all the script working for windows (aws ecr for example) and linux is frustrating at best and not workable at all realistically.

Why was this MR needed?

So we can sync images between registries more easily. This solution is quite portable with 0 shell scripting.

Also old code for pushing images is removed which cuts down on some old powershell and bash code.

I would like to merge this before !4072 (merged) so I can adapt the new code to the new alpine versions.

What's the best way to test this MR?

I am not sure we can truly test this until it's merged into main sadly. I think we can merge it into a stable branch but not really sure. The script itself can be tested with make REVISION=v15.11.0 sync_docker_images.

You should export the appropriate env variables e.g.:

PUSH_TO_DOCKER_HUB, PUSH_TO_ECR_PUBLIC, DOCKER_HUB_USER, DOCKER_HUB_PASSWORD

ECR credentials are generated from the aws's CLI. Get a correct access/secret key to generate a password.

What are the relevant issue numbers?

Closes #29449 (closed)