Allow Consolidator Reset

[AlexCatarino]

Expected Behavior

It is possible to reset consolidators.
Say we have a weekly or monthly consolidator, and a split occurs. The weekly/monthly bar will have pre- and post-split data:

We can workaround this issue by removing the consolidator from the subscription_manager, and create a new one.

    def reset_consolidator(self, symbol):
        self.subscription_manager.remove_consolidator(symbol, self.consolidator)
        self.consolidator: TradeBarConsolidator = self.consolidate(symbol, Calendar.WEEKLY, self.on_weekly_bar)

Ideally, this should be a simple reset method call as supported by indicators.

Actual Behavior

We cannot reset indicators.

Potential Solution

Add Reset method that sets the internal working data to null.

Reproducing the Problem

backtest #c52d5e

Checklist

• I have completely filled out this template
• I have confirmed that this issue exists on the current master branch
• I have confirmed that this is not a duplicate issue by searching issues
• I have provided detailed steps to reproduce the issue