Summary of the new feature / enhancement

It would make sense for some PS Modules to include extensions or even resources. SecretManagement makes sense to have a secret extension and AzPS also (for AzKeyVault).

Proposed technical implementation details (optional)

Add a new discover extension that searches PSModulePath for resources and extensions. Need to have some caching so that it doesn't crawl all the paths each time. It may be more efficient to also require the module manifest to declare it.