Update the autograding router to automatically decode sequence diagram strings

What problem are you trying to solve with Submitty At present, the router displays bytestrings to the user by default when rendering a sequence diagram.

Describe the way you'd like to solve this problem Use the python package cchardet to detect message encoding and decode.

Additional context This issue will require a new docker image submitty_autograding_router to be written. The package should run python and have cchardet installed.

The following code (or equivalent) should replace the sequence_diagram_message_preprocess function. The confidence threshold was chosen arbitrarily and is open to debate.

def sequence_diagram_message_preprocess(self, message):
    ret = message
    encoding_prediction = chardet.detect(message)
    if encoding_prediction['confidence'] > .8:
        try:
            ret = message.decode(encoding_prediction['encoding'])
        except:
            pass
    return re