Get the best route for an order

Prices a whole order across the QX order book and the QSwap pool and splits it where that pays more. Use side=sell to find what a holding would fetch and side=buy for what a purchase would cost: no wallet is needed, and a big order's price impact is already in the total. The summary field says the result in words (total, average, where each part goes, what the split is worth); route has each leg's exact figures and the limits to sign against.