Use "login" plugin instead of standalone JS file
Plugin "login" already has the same functionality as a JS code in
separated javascript file. There is no need to duplicate it.
Fixes: https://pagure.io/freeipa/issue/7619
Reviewed-By: Petr Vobornik <pvoborni@redhat.com>
Reviewed-By: Serhii Tsymbaliuk <stsymbal@redhat.com>