Clarify examples and read me

quickstart/201-machine-learning-private/variables.tf

@@ -1,7 +1,7 @@
 variable "name" {
   type        = string
   description = "Name of the deployment"
-  default     = "mlple999"
+  default     = "azureml568"
 }
 
 variable "environment" {
@@ -14,4 +14,16 @@ variable "location" {
   type        = string
   description = "Location of the resources"
   default     = "East US"
+}
+
+variable "vnet_address_space" {
+  type        = list(string)
+  description = "Address space of the subnet"
+  default     = ["10.0.0.0/16"]
+}
+
+variable "subnet_address_space" {
+  type        = list(string)
+  description = "Address space of the subnet"
+  default     = ["10.0.0.0/24"]
 }