webui: improve usability of attributes widget
    
    Attributes widget layour was changed from tiny table which allowed
    to display only few options to a checkbox list with multiple
    columns (depends on container).
    
    Check all attributes option was removed to force the user
    to read through the attributes which he selects.
    
    Initial version authored by: Adam Misnyovszki
    
    https://fedorahosted.org/freeipa/ticket/4253
    
    Reviewed-By: Endi Sukma Dewata <edewata@redhat.com>