Allow custom names and descriptions for load balancer components (#3223)

* feat: Changes for migrating resources to GLB module

* Updated Readme

* Added support for null description

* Added support for empty string

* Added default optional values

* Changed Readme

* Corrected description according to readme

* Added name and description changes for net-lb-app-ext-regional

* Added name and description changes for net-lb-app-int

* Added name and description changes for net-lb-app-int-cross-region

* Added name and description changes for net-lb-proxy-int

* Added name and description changes for net-lb-ext

* Added name and description changes for net-lb-int

* Changed Readme docs

modules/net-lb-app-ext/variables-urlmap.tf

@@ -19,6 +19,7 @@
 variable "urlmap_config" {
   description = "The URL map configuration."
   type = object({
+    description = optional(string, "Terraform managed.")
     default_custom_error_response_policy = optional(object({
       error_service = optional(string)
       error_response_rules = optional(list(object({