libvirt: Bump bootstrap memory to 5G

On ppc64le there were OOM kills being observed during the bootstrap process
because of insufficient memory and bumping the memory seemed to solve the problem.
The libvirt defaults for the master and worker memory are 7G and 5G respectively,
so setting the boostrap default to 5G.

data/data/libvirt/bootstrap/main.tf

@@ -13,7 +13,7 @@ resource "libvirt_ignition" "bootstrap" {
 resource "libvirt_domain" "bootstrap" {
   name = "${var.cluster_id}-bootstrap"
 
-  memory = "2048"
+  memory = "5120"
 
   vcpu = "2"