Non-public cloud support for Azure Data Explorer scaler.

[v-shenoy]

Support for cloud parameter in Data Explorer trigger metadata.

Sample ScaledObject definition -

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: kusto-so
spec:
  scaleTargetRef: 
    name: kusto-deployment
  pollingInterval: 10
  cooldownPeriod: 30
  minReplicaCount: 0
  maxReplicaCount: 2
  triggers:
    - type: azure-data-explorer
      metadata:
        tenantId: <tenant-id>
        clientId: <client-id>
        clientSecret: <client-secret>
        endpoint: <endpoint>
        databaseName: <database>
        cloud: "private" # Optional
        activeDirectoryEndpoint: <active-directory-endpoint> # Required when cloud = private
        query: <query>
        threshold: <threshold>

Documentation PR - kedacore/keda-docs#736

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 #2734

[JorTurFer]

LGTM!
Thanks!