feat: enable managing root password

- root password already set in common.eyaml
- add missing param to the accounts::root manifest
- remove if block as undef sshkeys has same effect

site/profiles/manifests/accounts/root.pp

@@ -1,12 +1,13 @@
 # manage the root user
 class profiles::accounts::root (
+  String $password,
   Optional[Array[String]] $sshkeys = undef,
 ) {
 
-  if $sshkeys {
-    accounts::user { 'root':
-      sshkeys => $sshkeys,
-    }
+  accounts::user { 'root':
+    username => 'root',
+    sshkeys  => $sshkeys,
+    password => $password,
   }
 
   file {'/root/.config':