Schema Validation for Scaled Deployment

When Loki is deployed with more than one node, an external object store needs to be used:

https://grafana.com/docs/loki/latest/storage/

When strategy==monolith && monolith.replicas != 1, we should error out if a local PVC is attempting to be used for storing logs

Same when strategy= scalable, we can't use a PVC at all since the read and write pods need to share data between them.