FTX: Margin lending/borrow rate history (#981)

* Adds lending rates/borrows to FTX and the command

* Movements, renames, rpc test

* Fleshing out rpc response

* Allows rpcserver to calculate offline (but not gctcli). Expands tests

* rn structs. add exchange_wrapper_issues support

* Adds a nice yearly rate

* Surprise yearly borrow rate!

* Rn+Mv to margin package. Fixes some serious whoopsies

* Adds average lend/borrow rates instead of sum

* rm oopsie whoopsie

* This is what the linter was having an issue with

* re-gen

* lintl

* niteroos

exchanges/margin/margin_types.go

@@ -0,0 +1,67 @@
+package margin
+
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+	"github.com/thrasher-corp/gocryptotrader/currency"
+	"github.com/thrasher-corp/gocryptotrader/exchanges/asset"
+)
+
+// 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
+	GetLendingPayments bool
+	GetBorrowRates     bool
+	GetBorrowCosts     bool
+
+	// CalculateOffline allows for the borrow rate, lending payment amount
+	// and borrow costs to be calculated offline. It requires the takerfeerate
+	// and existing rates
+	CalculateOffline bool
+	TakeFeeRate      decimal.Decimal
+	// Rates is used when calculating offline and determiningPayments
+	// Each Rate must have the Rate and Size fields populated
+	Rates []Rate
+}
+
+// RateHistoryResponse has the funding rate details
+type RateHistoryResponse struct {
+	Rates              []Rate
+	SumBorrowCosts     decimal.Decimal
+	AverageBorrowSize  decimal.Decimal
+	SumLendingPayments decimal.Decimal
+	AverageLendingSize decimal.Decimal
+	PredictedRate      Rate
+	TakerFeeRate       decimal.Decimal
+}
+
+// Rate has the funding rate details
+// and optionally the borrow rate
+type Rate struct {
+	Time             time.Time
+	MarketBorrowSize decimal.Decimal
+	HourlyRate       decimal.Decimal
+	YearlyRate       decimal.Decimal
+	HourlyBorrowRate decimal.Decimal
+	YearlyBorrowRate decimal.Decimal
+	LendingPayment   LendingPayment
+	BorrowCost       BorrowCost
+}
+
+// LendingPayment contains a lending rate payment
+type LendingPayment struct {
+	Payment decimal.Decimal
+	Size    decimal.Decimal
+}
+
+// BorrowCost contains the borrow rate costs
+type BorrowCost struct {
+	Cost decimal.Decimal
+	Size decimal.Decimal
+}