feat: Drop random pets from Managed Node Groups (#1372)

BREAKING CHANGES: We now decided to remove `random_pet` resources in Managed Node Groups (MNG). Those were used to recreate MNG if something change and also simulate the newly added argument `node_group_name_prefix`. But they were causing a lot of troubles. To upgrade the module without recreating your MNG, you will need to explicitly reuse their previous name and set them in your MNG `name` argument. Please see [upgrade docs](https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/docs/upgrades.md#upgrade-module-to-v1700-for-managed-node-groups) for more details.

examples/managed_node_groups/main.tf

@@ -78,7 +78,7 @@ module "eks" {
       max_capacity     = 10
       min_capacity     = 1
 
-      instance_types = ["m5.large"]
+      instance_types = ["t3.large"]
       capacity_type  = "SPOT"
       k8s_labels = {
         Environment = "test"