New Resource: azurerm_signalr_service_network_acl (#12434)

Currently, azurerm_signalr_service doesn't support to set network access control for SignalR.

After investigated, I think we cannot implement the networkACL property in azurerrm_signalr_service. Because service team confirmed that we must create private endpoint (Here private endpoint is created by azurerm_private_endpoint) which is referencing the existing SignalR resource (Here signalr resource is created by azurerm_signalr_service) first before updating the networkACL.privateEndpoint property of the existing SignalR resource. If we implement networkACL.privateEndpoint in azurerm_signalr_service, it would cause the issue of circular reference between azurerm_private_endpoint and azurerm_signalr_service. So we have to make this property as a separate resource.

Overview:
docs.microsoft.com/en-us/azure/azure-signalr/howto-network-access-control

azurerm/internal/services/signalr/registration.go

@@ -28,6 +28,7 @@ func (r Registration) SupportedDataSources() map[string]*pluginsdk.Resource {
 // SupportedResources returns the supported Resources supported by this Service
 func (r Registration) SupportedResources() map[string]*pluginsdk.Resource {
 	return map[string]*pluginsdk.Resource{
-		"azurerm_signalr_service": resourceArmSignalRService(),
+		"azurerm_signalr_service":             resourceArmSignalRService(),
+		"azurerm_signalr_service_network_acl": resourceArmSignalRServiceNetworkACL(),
 	}
 }