Build JSON API changes

pulp_sync: no longer accepts username and password parameters
pulp_sync: now accepts optional registry_secret_path, insecure_registry, and pulp_repo_prefix parameters, allowing sync from V2 registry that requires authentication -- note: this requires dockpulp > 1.22
tag_and_push: registries can now include a "secret" key in their description, which is the path to the Kubernetes dockercfg secret required for pushing to the registry
bump_release: no longer accepts git_ref, author_name, author_email, committer_name, committer_email, commit_message, or push_url
bump_release: now requires parameters target (Koji build target) and hub (Koji hub URL)
tag_from_config: new available plugin

Bug fixes

pulp_sync is now able to ask Pulp to sync from a V2 registry that requires authentication
bump_release now uses a Koji hub to discover the latest release of the component and uses that to provide a value for the Release label if missing
new tag_from_config plugin to add additional tags to the image