Add better method for redrawing chart

[blackary]

Right now it's a pain to redraw the chart if you don't call .animate, for example if the underlying data changes upstream -- need to figure out a way to allow the user to set the key easily based on a set of values. For example, I can set the key myself using a method like this

def hash_things(*things: Any) -> str:
    return hashlib.sha256("".join(str(t) for t in things).encode("utf-8")).hexdigest()

And then setting the key like:

VizzuChart(key=hash_things(start_date, end_date)

Where I pass in a set of values, or perhaps even the dataframe underlying the data. This should be an easier way to set this.