Separate Docker build/publish actions

[sgoings]

Today: Right now the Docker task publishes to the registry depending on a boolean which can be configured per task. This conflation of task responsibility seems to go against the Docker and Gradle way of handling artifact publishing (where there are separate tasks for building and publishing).

The Future: I'd like to get your ideas on what you have in your minds for improving the workflow of Docker image build/publishing... I think it would be neat to wrangle the Docker publishing under the same (or similar) DSL that Gradle provides for artifact publishing (Maven/Ivy).

[mattgruter]

Agreed! Not sure yet how docker publishing aligns with gradle's publishing APIs. But a seperation of build and publish is necessary independent of how the publish will look like in the end. Not sure if I manage to squeeze it into the upcoming 1.3 release.