Replace existing Travis solution for automating the creation of new releases

[Smudgey]

The existing Travis solution is no long available for us to use. As such, we need to find a replacement. Unfortunately, the sky-uk org is not providing replacement capabilities at the moment, so we need to find a new long-term solution.

In the interim, pipelines will be set up on internal sky tooling for pushing new images that we can use in our deployments.