fix(setup): allow admin creation via arguments

In addition to allowing input via prompt (to hide passwords), we added
support for input via arguments. This way, remote command like on Heroku
will work.

#56
fix(list): require admin permissions to access

Anyone attempting to access the User List page at /user/list without
logging in first or without admin permissions will receive a 403
Forbidden instead.

#61
style(setup):

Refactor code and remove unnecessary code.

#56
improve(engine): use engine.io to load user list

The User List will now use engine.io to load users from the server.
Also, when changing the sort order, the client will sort already loaded
users, and new "load more" requests will honor the new sort order, and
automatically sort them in as loaded.

#58
fix(list): error with loading users in user list

Was using the incorrect variable for loading users, so would always use
the default arguments.

#58
new admin users are now in the 'local' group