Binance,OKx: Implement fetching funding rates (#1239)

* adds basic groundwork for rates on binance

* more into rates on binance

* rm redudant redundancy, add payments

* mini commit before merging with testnet ability branch

* changes function signature and fixes resulting build

* gets billing data too

* funding rates package, features use, testnet reimpl

* new endpoint, refinements and tests

* cli fix, rpc impl, testing, payments

* fixups from looking at code

* typo fix

* niteroos

* merge fixes

* adds test, fixes cli issues

* woah nelly

exchanges/margin/margin_types.go

@@ -10,12 +10,14 @@ import (
 
 // RateHistoryRequest is used to request a funding rate
 type RateHistoryRequest struct {
-	Exchange           string
-	Asset              asset.Item
-	Currency           currency.Code
-	StartDate          time.Time
-	EndDate            time.Time
-	GetPredictedRate   bool
+	Exchange         string
+	Asset            asset.Item
+	Currency         currency.Code
+	Pair             currency.Pair
+	StartDate        time.Time
+	EndDate          time.Time
+	GetPredictedRate bool
+
 	GetLendingPayments bool
 	GetBorrowRates     bool
 	GetBorrowCosts     bool