Enable logging to AzureML workspace 2 when running in AzureML workspace 1

[ant0nsc]

To decouple experiment results from runs, it would be great to log not only to the current AML workspace, but to second one that only holds experiments (no data).

This should be doable by extending the existing MLFlow logger. We would need means of authenticating to the logging workspace, for example by reading a password from keyvault.