Change optparse with argparse
    
    The previous version used the optparse module that has been deprecated
    for some time already and Pylint would constantly warn about it.
    The PR replaces optparse with argparse while retaining the logic
    to add searching patterns on the CLI, similarly to other CLI tools,
    such as ls, etc.
    
    Fixes: https://pagure.io/fedora-easy-karma/issue/41
    Merges: https://pagure.io/fedora-easy-karma/pull-request/45
    
    Fix crashing when --help called.
    
    Fix the placeholders that are used to fill in default values.
    Rewrite the USAGE variable a little bit in order not to duplicate
    the usage info.
    
    probably wrongly-merged rebase
    
    reflow the usage text a bit better
    
    extras -> pattern
    
    Extras was confusing, pattern is clear (it's also mention in usage the same
    way).