Support managed identity, Key Vault managed keys

### Is your feature request related to a problem? Please describe.
Security feature request

### Describe the solution you'd like

Provide support for managed identity / other methods of secure authentication to the service besides API Key.
Manage key rotations with Key Vault to remove any need to rotate keys manually or via scripts.
and provide samples when working with the secret portions of the code.

See

### Additional context
Add any other context or screenshots about the feature request here.

The issue names no files, tests, or entry points. Start by locating the service authentication and key-management areas, then review the linked Azure Key Vault storage-keys documentation. Done should include managed identity or another secure authentication method, Key Vault-managed key rotation, and samples for handling secret portions of the code.

Written by the indexing model from the issue text.