Docker Ubuntu image should be defined using rules_docker, not Bash scripts

[alexjpwalker]

We have an example of defining an image using rules_docker in TypeDB, namely:

• @vaticle_typedb//:assemble-docker
• @vaticle_typedb//:assemble-docker-bundle
• @vaticle_typedb//:deploy-docker

We should standardise and use this setup for our Docker Ubuntu image too.