Create container to avoid local dependencies

[absoludity]

Currently a bunch of dependencies are required for local installation (carvel tools, kind, yq, etc.) as documented in the CONTRIBUTING.md.

We should build and publish a container to simplify the running of the script.

[castelblanque]

Outstanding task is:

• Completely automate the process by adding to the container the Git and GitHub credentials so that commits and releases can be automatically done from it.