Replace Spotify docker-client with an alternative

[chadlwilson]

The client currently used is effectively EOL: https://github.com/spotify/docker-client

It also has a lot of dependencies on other libraries which cannot be upgraded (e.g Jersey) who themselves have reported vulnerabilities (which may or may not be relevant to this plugin)

Probably should move to https://github.com/docker-java/docker-java ?

See gocd/docker-registry-artifact-plugin#874 and gocd-contrib/docker-elastic-agents-plugin#258