Add Azure Stack as a valid environment

Adds AzureStack as a valid cloud environment. The value
"AzureStackCloud" corresponds to the name expected by the azure
autorest package, which will expect a environment configuration
file to be found at a path specified by the environment variable
AZURE_ENVIRONMENT_FILEPATH. See:

https://github.com/Azure/go-autorest/blob/main/autorest/azure/environments.go#L300-L302

Author: patrickdillon

api/v1beta1/types_class.go

@@ -48,6 +48,7 @@ type AzureClusterClassSpec struct {
 	// - GermanCloud: "AzureGermanCloud"
 	// - PublicCloud: "AzurePublicCloud"
 	// - USGovernmentCloud: "AzureUSGovernmentCloud"
+	// - StackCloud: "AzureStackCloud"
 	//
 	// Note that values other than the default must also be accompanied by corresponding changes to the
 	// aso-controller-settings Secret to configure ASO to refer to the non-Public cloud. ASO currently does
@@ -186,6 +187,7 @@ type AzureManagedControlPlaneClassSpec struct {
 	// - PublicCloud: "AzurePublicCloud"
 	// - USGovernmentCloud: "AzureUSGovernmentCloud"
 	//
+	//
 	// Note that values other than the default must also be accompanied by corresponding changes to the
 	// aso-controller-settings Secret to configure ASO to refer to the non-Public cloud. ASO currently does
 	// not support referring to multiple different clouds in a single installation. The following fields must

azure/defaults.go

@@ -44,6 +44,8 @@ const (
 	ChinaCloudName = "AzureChinaCloud"
 	// USGovernmentCloudName is the name of the Azure US Government cloud.
 	USGovernmentCloudName = "AzureUSGovernmentCloud"
+	// StackCloudName is the name for Azure Stack hybrid cloud environments.
+	StackCloudName = "AzureStackCloud"
 )
 
 const (

config/crd/bases/infrastructure.cluster.x-k8s.io_azureclusters.yaml

@@ -92,6 +92,7 @@ spec:
                   - GermanCloud: "AzureGermanCloud"
                   - PublicCloud: "AzurePublicCloud"
                   - USGovernmentCloud: "AzureUSGovernmentCloud"
+                  - StackCloud: "AzureStackCloud"
 
                   Note that values other than the default must also be accompanied by corresponding changes to the
                   aso-controller-settings Secret to configure ASO to refer to the non-Public cloud. ASO currently does

config/crd/bases/infrastructure.cluster.x-k8s.io_azureclustertemplates.yaml

@@ -65,6 +65,7 @@ spec:
                           - GermanCloud: "AzureGermanCloud"
                           - PublicCloud: "AzurePublicCloud"
                           - USGovernmentCloud: "AzureUSGovernmentCloud"
+                          - StackCloud: "AzureStackCloud"
 
                           Note that values other than the default must also be accompanied by corresponding changes to the
                           aso-controller-settings Secret to configure ASO to refer to the non-Public cloud. ASO currently does