exchanges/futures: Implement open interest (#1417)

* adds open interest to exchanges

* ADDS TESTING YEAH

* New endpoints, BTSE, RPCS, cached

* slight design change, begin gateio

You will need to get cached for
each exchange that supports it

* gateio, huobi, rpc

* fix up kraken, cache retrieval

* okx, gateio

* finalising all implementations and tests

* definitely my final ever commit on this

* Well, well, well

* final v2

* quick fix of bug

* test coverage, assert notempty, test helper

Added a new testhelper for currency
management because its very annoying
in a parallel test setting which wastes
so much space otherwise

* minimises REST requests for Open Interest

* types.Number merge misses

* Minimises Kraken REST calls

* len change, value -> pointer receiver

* further fixup

* fixes gateio, batch calculates open interest

* single gateio, lint const fixes

* rejig and more thorough oi for huobi

* formatting expansion

* minor fix for handling expiring contracts

* rm unused Binance strings

* add bybit support, fix bybit issues

* oopsie doopsie, dont look at my whoopsie

* Fix issue, remove feature

* move an irrelevant function for the pr

* mini bybit upgrades

* fixes cli request bug

engine/event_manager_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/thrasher-corp/gocryptotrader/currency"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/asset"
+	"github.com/thrasher-corp/gocryptotrader/exchanges/ticker"
 )
 
 func TestSetupEventManager(t *testing.T) {
@@ -299,7 +300,7 @@ func TestCheckEventCondition(t *testing.T) {
 	}
 	m.m.Lock()
 	err = m.checkEventCondition(&m.events[0])
-	if err != nil && !strings.Contains(err.Error(), "no tickers associated") {
+	if err != nil && !errors.Is(err, ticker.ErrNoTickerFound) {
 		t.Error(err)
 	} else if err == nil {
 		t.Error("expected error")