Add Azure Key Vault support and enhance credential handling in configuration data

Public/Register-DSCConfigurationDataCredentialProvider.ps1

@@ -25,6 +25,14 @@ function Register-DSCConfigurationDataCredentialProvider {
         [hashtable]
         $VaultParameters = @{},
 
+        [Parameter(Mandatory=$false)]
+        [string]
+        $SubscriptionId,
+
+        [Parameter(Mandatory=$false)]
+        [string]
+        $TenantId,
+
         [Parameter(Mandatory=$false)]
         [switch]
         $RegisterVault,
@@ -239,6 +247,29 @@ function Register-DSCConfigurationDataCredentialProvider {
                     return $ProviderSettings
                 }
             }
+            "AzureKeyVault" {
+                $ProviderSettings = [ordered]@{
+                    AzureKeyVault = [ordered]@{
+                        DefaultVault = $Vault
+                    }
+                }
+
+                if(-not [string]::IsNullOrWhiteSpace($SubscriptionId)){
+                    $ProviderSettings["AzureKeyVault"]["SubscriptionId"] = $SubscriptionId
+                }
+
+                if(-not [string]::IsNullOrWhiteSpace($TenantId)){
+                    $ProviderSettings["AzureKeyVault"]["TenantId"] = $TenantId
+                }
+
+                if($PSCmdlet.ShouldProcess($SettingsPath, "Create provider settings for [$Provider]")){
+                    Export-PowerShellDataFile -InputObject $ProviderSettings -Path $SettingsPath -Force:$Force
+                }
+
+                if($PassThru){
+                    return $ProviderSettings
+                }
+            }
             default {
                 throw "Provider [$Provider] does not provide an initialization implementation."
             }