passwordless-root: sudo: grant access for group qubes

For consistency with `su` and policykit, grant access to group
qubes rather than user user.

passwordless-root/qubes.sudoers

@@ -1,5 +1,5 @@
 Defaults !requiretty
-user ALL=(ALL) NOPASSWD: ALL
+%qubes ALL=(ALL) NOPASSWD: ALL
 
 # WTF?! Have you lost your mind?!
 #