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

common/convert/convert.go

@@ -226,3 +226,10 @@ func (f *StringToFloat64) UnmarshalJSON(data []byte) error {
 func (f *StringToFloat64) Float64() float64 {
 	return float64(*f)
 }
+
+// Decimal returns the decimal value of the FloatString
+// Warning: this does not handle big numbers as the underlying
+// is still a float
+func (f *StringToFloat64) Decimal() decimal.Decimal {
+	return decimal.NewFromFloat(float64(*f))
+}

common/convert/convert_test.go

@@ -355,6 +355,20 @@ func TestStringToFloat64(t *testing.T) {
 	}
 }
 
+func TestStringToFloat64Decimal(t *testing.T) {
+	t.Parallel()
+	resp := struct {
+		Data StringToFloat64 `json:"data"`
+	}{}
+	err := json.Unmarshal([]byte(`{"data":"0.00000001"}`), &resp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !resp.Data.Decimal().Equal(decimal.NewFromFloat(0.00000001)) {
+		t.Errorf("received '%v' expected '%v'", resp.Data.Decimal(), 0.00000001)
+	}
+}
+
 // 2677173	       428.9 ns/op	     240 B/op	       5 allocs/op
 func BenchmarkStringToFloat64(b *testing.B) {
 	resp := struct {