Add the possibility to filter the user's issues by dates
    
    This commit add support for filtering the issues returned by the
    ``/api/0/user/<username>/issues`` API endpoint by dates either one of:
    creation date, last update or close date.
    
    Fixes https://pagure.io/pagure/issue/4064
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>