Feature Request: Add flag to registry push that pushes composed components

[fibonacci1729]

With the introduction of component dependencies pre-existing runtimes are unable to reconcile the new Spin locked app format (e.g. SpinKube). This flag would indicate to spin registry push to compose Spin components with their dependencies (before publishing to a registry) resulting in an artifact that contains the dependency-erased components. The obvious downside of this approach is that component layers for applications can't be deduplicated in OCI or across the wire; however this flag would assist in running applications that use dependencies in these runtimes.

cc/ @kate-goldenring @michelleN