Form validation on login page

Using ngMessages, adds form validation to login page. Also creates a
directive, hasError, to be used to validate form field by passing
in a boolean. This is a proposed pattern to be used moving forward,
as form validation is added to additional pages.

Validation error messages are shown on $touched and on submit.
Unreachable Server and Invalid username and password error messages
remain until input is no longer $pristine after form submission.

In addition, this removes unneeded and unused css styling

Resolves openbmc/phosphor-webui#47

Change-Id: I7a067af67ac74d4cf2977d10f66445720ecae9eb
Signed-off-by: beccabroek <beccabroek@gmail.com>
diff --git a/app/index.js b/app/index.js
index 37e27c1..2313016 100644
--- a/app/index.js
+++ b/app/index.js
@@ -54,6 +54,7 @@
 import paginate from './common/directives/paginate.js';
 import serial_console from './common/directives/serial-console.js';
 import dir_paginate from './common/directives/dirPagination.js';
+import form_input_error from './common/directives/form-input-error.js';
 
 import login_index from './login/index.js';
 import login_controller from './login/controllers/login-controller.js';