Auto-fallback provider for Kerberos Vault

[cedricve]

Currently it's only possible to store in a single provider, however:

1. a provider might become unavailable for a long time,
2. there is a need to load balance providers (different clouds, different datacenters, hybrid storage (edge/cloud storage)
3. regionality: depending on a header defined in Kerberos Agent or Kerberos Factory a recording might be stored in a specific storage location.

With this feature we will provide a solution for above scenarios, giving another compelling edge to our scalable solution stack.