Add support for Azure VMSS Flexible Orchestration to Fleeting + Taskcaler

Problem to solve

Azure VMSS recommends Flexible Orchestration mode for Azure Virtual Machine Scale Sets. Customers attempting to use the Runner with Fleeting + Taskscaler on Azure have run into configuration issues due to the customers setting up VMSS with Flexible Orchestration.

Additional context

• For flex VMSS the individual instances need to be managed and queried not as we do right now, via "VMSS APIs", but directly via the "plain VM APIs".

Proposal

Add support for Azure VMSS Flexible Orchestration mode to Fleeting + Taskcaler

Implementation tasks

• Placeholder