protected RegistryService.RegistryConfig getRegistryConfig(String specificRegistry) {
        return new RegistryService.RegistryConfig.Builder()
                .settings(settings)
                .authConfig(authConfig != null ? authConfig.toMap() : null)
                .authConfigFactory(authConfigFactory)
                .skipExtendedAuth(skipExtendedAuth)
                .registry(specificRegistry != null ? specificRegistry : registry)
                .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