Update login form messaging

web/views/login.erb

 <div class="container">
-  <h2 class="container__heading">Login</h2>
   <form class="form form--login" action="/login" method="POST">
+    <p>Log in with your VLV credentials</p>
     <% if error_message %>
       <p class="error"><%= error_message %></p>
     <% end %>