Packet Quickstart: add machine types to the example config

Currently it's not possible to deploy the latest lokomotive release on
Packet without specifying the machine type. Figuring out the right
parameters in the config takes a while. Make this easier by adding them
to the example config.

docs/quickstarts/packet.md

@@ -116,6 +116,8 @@ cluster "packet" {
   facility = "ams1"
   project_id = "89273817-4f44-4b41-9f0c-cb00bf538542"
 
+  controller_type = "c3.small.x86"
+
   ssh_pubkeys       = ["ssh-rsa AAAA..."]
   management_cidrs  = ["0.0.0.0/0"]
   node_private_cidr = "10.0.0.0/8"
@@ -124,6 +126,7 @@ cluster "packet" {
 
   worker_pool "pool-1" {
     count       = 2
+    node_type = "c3.small.x86"
   }
 }