Non-public cloud support for Azure Monitor scaler.

[v-shenoy]

Signed-off-by: Vighnesh Shenoy vshenoy@microsoft.com

Supporting non-public clouds for the Azure Monitor scaler using the cloud parameter.

Sample ScaledObject definition -

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: monitor-so
spec:
  scaleTargetRef: 
    name: monitor-deployment
  pollingInterval: 10
  cooldownPeriod: 30
  minReplicaCount: 0
  maxReplicaCount: 2
  triggers:
    - type: azure-monitor
      metadata:
        resourceURI: <resource-uri>
        tenantId: <tenant-id>
        subscriptionId: <subscription-id>
        resourceGroupName: <rg-name>
        targetValue: <target>
        metricName: <metric-name>
        metricAggregationType: <metric-agg-type>
        cloud: "private" 
        resourceManagerEndpoint: <resource-manager-endpoint>
        activeDirectoryEndpoint: <active-directory-endpoint>
      authenticationRef:
        name: monitor-ta

Documentation PR - kedacore/keda-docs#735

Checklist

• Commits are signed with Developer Certificate of Origin (DCO - learn more)
• Tests have been added
• A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• A PR is opened to update the documentation on (repo) (if applicable)
• Changelog has been updated and is aligned with our changelog requirements

Fixes #1917

[JorTurFer]

LGTM!
Some comments inline