feat: Add a homemade depends_on for MNG submodule to ensure ordering of resource creation (#867)

modules/node_groups/variables.tf

@@ -34,3 +34,11 @@ variable "node_groups" {
   type        = any
   default     = {}
 }
+
+# Hack for a homemade `depends_on` https://discuss.hashicorp.com/t/tips-howto-implement-module-depends-on-emulation/2305/2
+# Will be removed in Terraform 0.13 with the support of module's `depends_on` https://github.com/hashicorp/terraform/issues/10462
+variable "ng_depends_on" {
+  description = "List of references to other resources this submodule depends on"
+  type        = any
+  default     = null
+}