[users] Make the example config usable

Although the example configurations shouldn't really be used
as a sample of how to configure **your** Calamares for your
distro, many distro's do just copy the examples. So leave
traces of the OEM-configuration settings in the example,
and give the standard configuration a 'nothing changed'
set of presets.

src/modules/users/users.conf

@@ -162,8 +162,8 @@ writeHostsFile: true
 
 presets:
     fullName:
-        value: "OEM User"
-        editable: false
+        # value: "OEM User"
+        editable: true
     loginName:
-        value: "oem"
-        editable: false
+        # value: "oem"
+        editable: true