Deploy Scenario from feast examples

**Is your feature request related to a problem? Please describe.**
Currently, Feast allows to init the feast which deploys the feature_repo for given DB backend. But we don't provide a way to deply the feature repo for scenarios like `RAG` etc.

**Describe the solution you'd like**
Feast should be able to deploy the scenario feature repo from examples:
```
# feast init --scenario rag
```