feat(images): add multi-platform images for garden deployed services

[twelvemo]

What this PR does / why we need it:

Adds multi-platform builds for all the garden deployed containers like buildkit, skopeo, k8s-sync, etc. This allows users to run garden on arm64 native kubernetes.

We can not use the publish command any longer to publish the images to dockerhub, since the docker-container buildx runner is not able to load the images in the default local docker image store. To facilitate this, we now always push to DockerHub when running garden build in this project, but with a dev tag. When running garden build --var publish=true we push them with the specified production tag in release_tag. This is a temporary workaround until we have properly integrated mutli-platform building into garden.

Also moves the images project from modules to actions ;-)

Which issue(s) this PR fixes:

Fixes #6088

Special notes for your reviewer:

[vvagaytsev]

Nice! Let's also explicitly define spec.publishId for all images.

[twelvemo]

Nice! Let's also explicitly define spec.publishId for all images.

We can't really use it yet, because we can't use the publish command, instead we have to run garden build --var publish=true. I wrote some more detailed explanations in the README.

[vvagaytsev]

We can't really use it yet, because we can't use the publish command, instead we have to run garden build --var publish=true. I wrote some more detailed explanations in the README.

Ah, I see! Thank you :)