Azure Blob Storage support in CAS

[migmartri]

Add support to Azure Blob Storage as CAS backend.

This feature will also require to prepare the CAS service to support multiple backend types

### Pre-requisites
- [x] [Proxy] Multiple Backends support https://github.com/chainloop-dev/chainloop/pull/359
- [x] [Proxy] Selection on the fly https://github.com/chainloop-dev/chainloop/pull/359
- [x] [CLI] Send CAS backend type to Proxy for selection https://github.com/chainloop-dev/chainloop/pull/359

and once done we can move ahead with the actual upload/download implementation in the proxy

### Azure blob manager in CAS proxy
- [x] Look into authentication mechanisms https://github.com/chainloop-dev/chainloop/pull/360
- [x] Implement upload/download methods + metadata retrieval https://github.com/chainloop-dev/chainloop/pull/360

and the UX in the controlplane-CLI

### Azure CAS backend in control plane
- [x] Selection, addition, onboarding https://github.com/chainloop-dev/chainloop/pull/360