Remove UID from all users

We don't need preconfigure it. This way it won't change the UID of
existing accounts, having to recreate them in the process.

data_bags/users/bumi.json

@@ -4,6 +4,5 @@
     "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC9dnAq8JP9SfWT4xwKEQudKKd7IFhGaQDXluNJCO2aRWQHNALMg27vkp7ZEdAYE8xdm2iguoEZAs8pCdxHSuO2pwsYn6uC1AYpp5ewXBFz4ljjZxl9GWOel3RhhLrRbQpjti7T12LB5SUSKSm0lm4O2nFnjgVey41zDkV94YXT1biHs/gZxRsNnnptfXMa5AKwkEnNK/3JkhDMO2dgKpf8j6GPO5y+QhS3lzCBS9pCAgOGqaPr+kXaQo70MxTi7FP+4GkwwVctP7bXLzrRyUdgRia65P8zKFOpOyAJt5E1fB5DcaGEdyHXijbWNdb/qE/eHo7W1bGSsNJ1JYgZOtAB 2015 hello@michaelbumann.com"
   ],
   "groups": ["sysadmin", "systemd-journal"],
-  "uid": 2003,
   "shell": "\/bin\/bash"
 }