[FEATURE] Add support for predefined existing resource

### Your suggestion

In https://github.com/microsoft/PSRule/issues/3105 @riosengineer describes several cases where the ability to reference existing resource state from Azure in deployments/ deployment stacks is ideal.

We should add the ability to define an existing resource such as a deployment stack or shared infrastructure that can be used instead of a mock resource.

Since the ability to export resources from Azure for in-flight analysis already exists, this is a logical extension of that functionality but allows that exported data to be exposed for pre-flight analysis.

These exported resources could be committed to the repository or generated by some other process at runtime.

### Alternatives

While mocking generally works, it performs poorly in the cases when you are trying to reference a deployment/ deployment stack output from a previous deployment that is not deployed through the current deployment.

### Additional context

Separate work items should also look to:

- Perform automatic extraction of these directly from Azure - https://github.com/Azure/PSRule.Rules.Azure/issues/3658
- Implement a caching or way to store these definitions for use across multiple repositories in an enterprise - https://github.com/Azure/PSRule.Rules.Azure/issues/3659