Tweak bug print format, print combined bug list too
    
    This is a somewhat more useful info string for bugs in this
    context; compared to the one we get with just `print(bug)`, this
    drops the assignee (which we don't really care about here) but
    adds the resolution (which we do).
    
    Also, when running with `-l`, as well as printing the bugs for
    each test day as it goes, this prints a summary of all unique
    bugs across all test days at the end.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>