Backstage Plugin Enhancements

It would be amazing to have the backstage plugin capable of working more like the Jenkins plugin. This plugin has multiple features, but the two most useful would be.

1. A user can annotate the catalog-info.yaml file with a spacelift.io/stacks tag and then be able to list stacks specific to a Backstage component. This would prevent users from having to filter through a thousand or more stacks with the global plugin.

2. Backstage scaffolder actions that would be able create and manage existing stacks. This would allow the workflow to automatically create a backstage stack at the time the repository is created.