Support BYOK in Microsoft Fabric

Bring-Your-Own-Key aka. Customer-Managed Keys for encryption is a mandatory requirement in many companies to ensure compliance with GDPR and internal security regulations. As long as Fabric doesn't support BYOK, we can't use it's full potential.

Key Vaults must be assignable on workspace-level or lower, e.g. per lakehouse, so that we can reduce the risk of a compromised key by decentralizing the key management. Defining one Key Vault per Workspace would imho be the best balance between decentralization and maintenance effort.