protected BuildService.BuildContext getBuildContext() {
        return new BuildService.BuildContext.Builder()
          .buildArgs(buildArgs)
          .mojoParameters(createMojoParameters())
          .registryConfig(getRegistryConfig(pullRegistry))
          .build();
    }
Entry point for this plugin. It will set up the helper class and then calls
{@link #executeInternal(ServiceHub)}
which must be implemented by subclass.

@throws MojoExecutionException
@throws MojoFailureException
src/main/java/io/fabric8/maven/docker/AbstractDockerMojo.java