Azure Stack Hub HybridEnvironment Support

[patrickdillon]

/kind feature

Describe the solution you'd like
Support using CAPZ to provision clusters on Azure Stack Hub.

Anything else you would like to add:
Achieving this goal would entail:

• Adding Azure Stack Cloud (or HybridEnvironment) as a valid AzureEnvironment
• Configuring cloud endpoints for the azure stack environment
• Adding support for Basic Load Balancers (only supported LB on Azure Stack Hub)
• Updating API version to a compatible profile as necessary (I believe this is only needed for resources that are not provisioned using ASO, so we can either migrate them to ASO or update the profiles. I'm currently working through NSGs, not sure if more are needed).

Environment:

• cluster-api-provider-azure version:
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):