Forms based authentication UI
    
    Support for forms based authentication was added to UI.
    
    It consist of:
    
    1) new login page
    Page url is [ipa server]/ipa/ui/login.html
    
    Page contains a login form. For authentication it sends ajax request at [ipa server]/session/json/login_password. If authentication is successfull page is redirected to [ipa server]/ipa/ui if it fails from whatever reason a message is shown.
    
    2) new enhanced error dialog - authorization_dialog.
    
    This dialog is displayed when user is not authorized to perform action - usually when ticket and session expires.
    It is a standard error dialog which shows kerberos ticket related error message and newly offers (as a link) to use form based authentication. If user click on the link, the dialog content and buttons switch to login dialog which has same functionality as 'new login page'. User is able to return back to the error message by clicking on a back button.
    
    login.html uses same css styles as migration page -> ipa-migration.css was merged into ipa.css.
    
    https://fedorahosted.org/freeipa/ticket/2450