Get restarts working

[eristoddle]

Right now i can restart the jobs on launch, but although it picks up the strategy from the database and doesn't duplicate that, each run of the strategy is unique. This does not matter much on backtests or even simulation. But with live trading, if something crashes the workers:

• i want them to come back up and pick up where they left off.
• i want them to know how many positions are open.
• I want them to figure out the gap between the current candle and the last and use that data to calculate what should be done but not trade until caught up.
• I want them to pick up the last run key. And maybe need to store an extra state key in json data, to signify worker downtime when running stats.

This a pretty complex problem