ci: zkevm contracts docker image builder

[leovct]

Description

• Move the automated docker build workflow from my zkevm-contracts fork to the kurtosis-cdk repository.
• Update the docker docs.

Test

The tests have been performed on my fork of the kurtosis-cdk repository. They required the creation of two new secrets, IMAGE_BUILDER_DOCKERHUB_USERNAME and IMAGE_BUILDER_DOCKERHUB_TOKEN.

1. Build and push images that already exist on the Docker Hub.

The workflow should skip the build and push part.

• v8.1.0-rc.1-fork.13: https://github.com/leovct/kurtosis-cdk/actions/runs/11703871078/job/32595118786
• v9.0.0-rc.2-pp: https://github.com/leovct/kurtosis-cdk/actions/runs/11704008932

2. Build and push images that don't exist on the Docker Hub.

The workflow should push the images to the Docker Hub.

• v9.0.0-rc.3-pp: https://github.com/leovct/kurtosis-cdk/actions/runs/11704067376 and new image pushed to the docker hub
• 4912f4b: https://github.com/leovct/kurtosis-cdk/actions/runs/11704070098 (the image has been deleted from the docker hub)

References (if applicable)

• Follow up of docs: update docker docs #351.
• https://polygon.enterprise.slack.com/lists/T8VPLGV4Z/F07AWFULS49?record_id=Rec07V48FFZDF