Update to Realised PNL Accounting

For simplicity, we have made a small change to how we show Realised PNL on the frontend.

Previously, Realised PNL for all positions included all PNL since that contract was listed, regardless of whether or not your position had closed. Now, if you close any position (that is, your quantity is exactly 0, Realised PNL is reset to 0, and moved to the Closed Positions tab. These values are also available in your Wallet History.

Life-to-date PNL for all contracts, as well as total Deposits and Withdrawals, is now available via a new API endpoint (docs).