fix(misc): contrib/terraform/aws (#7818)

* fix(misc): terraform/aws

- handles deployment with a single availability zone
- handles deployment with more than two availability zone
- handles etcd collocation with control-plane nodes (`aws_etcd_num=0`)
- allows to set a bastion instances count (`aws_bastion_num`)
- allows to set bastion/etcd/control-plane/workers rootfs volume size
- removes variables from terraform.tfvars that were not re-used
- adds .terraform.lock.hcl to .gitignore
- changes/updates base image from ubuntu-18.03 to debian-10

tested by a few coworkers of mine, and myself: thanks for the outstanding
work, on both those terraform samples and kubespray playbooks.
I did not test ubuntu deployments, I could still swap from buster to
focal. LMK.

* fix(gitlab-ci)

AFAIU, terraform.tfvars indentation should be fixed for / no diff
returned running `terraform fmt -check -diff`

https://gitlab.com/kargo-ci/kubernetes-sigs-kubespray/-/jobs/1445622114

contrib/terraform/aws/sample-inventory/cluster.tfvars

@@ -9,6 +9,8 @@ aws_cidr_subnets_private = ["10.250.192.0/20", "10.250.208.0/20"]
 aws_cidr_subnets_public = ["10.250.224.0/20", "10.250.240.0/20"]
 
 #Bastion Host
+aws_bastion_num = 1
+
 aws_bastion_size = "t2.medium"
 
 #Kubernetes Cluster
@@ -17,22 +19,26 @@ aws_kube_master_num = 3
 
 aws_kube_master_size = "t2.medium"
 
+aws_kube_master_disk_size = 50
+
 aws_etcd_num = 3
 
 aws_etcd_size = "t2.medium"
 
+aws_etcd_disk_size = 50
+
 aws_kube_worker_num = 4
 
 aws_kube_worker_size = "t2.medium"
 
+aws_kube_worker_disk_size = 50
+
 #Settings AWS ELB
 
 aws_elb_api_port = 6443
 
 k8s_secure_api_port = 6443
 
-kube_insecure_apiserver_address = "0.0.0.0"
-
 default_tags = {
   #  Env = "devtest"  #  Product = "kubernetes"
 }