Support `azd pipeline config` for extensions

azd pipeline config doesn't produce the right artifacts for creating, deploying, etc. Foundry agents.

When using the azure ai * extensions, we want to be able to make it simple for devs to setup CI/CD for Foundry scenarios.

```
Configure your GitHub pipeline

ERROR: failed to initialize infra provider microsoft.foundry: initializing infrastructure provider: failed resolving IaC provider 'microsoft.foundry': failed resolving instance from container: container: no concrete found for: provisioning.Provider
```