docs: show dev VM specs dynamically

metal/Vagrantfile

@@ -3,6 +3,14 @@ require 'yaml'
 inventory = YAML.load_file(File.join(__dir__, './inventories/dev.yml'))
 group_vars = YAML.load_file(File.join(__dir__, './group_vars/all.yml'))
 
+# ANCHOR: vm_specs
+# TODO This is ridiculous for a local development environment.
+# After multi-env is supported, optimize it.
+cpus = 4
+memory = "10240"
+disk_size = "256GB"
+# ANCHOR_END: vm_specs
+
 Vagrant.configure("2") do |config|
   config.vm.box = "rockylinux/8"
 
@@ -12,15 +20,14 @@ Vagrant.configure("2") do |config|
         ip = host_vars['ansible_host']
         node.vm.network "public_network", ip: ip
         node.vm.hostname = host
-        node.vm.disk :disk, size: "256GB", primary: true
+        node.vm.disk :disk, size: disk_size, primary: true
       end
     end
   end
 
   config.vm.provider "virtualbox" do |vb|
-    # TODO this is ridiculous for a local environment, optimize it
-    vb.cpus   = 6
-    vb.memory = "10240"
+    vb.cpus   = cpus
+    vb.memory = memory
   end
 
   config.vm.provision "file",