exchanges: Update OKCoin V5 exchange support (#1206)

* starting public endpoints

* Adding public endpoints

* added public spot market endpoints

* websocket subscriptions updates

* websocket push data handlers completing

* linter fix

* Added funding private endpoints

* Adding authenticated account endpoints

* Added fiat and OTC-RFQ authenticated endpoints

* trading authenticated endpoints

* completing trade endpoints and add public wrapper endpoints

* Authenticated wrapper functions and corresponding unit test

* Adding authenticated websocket endpoint and fixing wrapper functions

* Documentation and exchange websocket update

* update websocket orderbook checksum handling

* linter issues fix and unit test update

* remove invalid orderbook endpoint and unit test

* Documentation, handlers, and model types update

* minot fix

* Minor fixes

* Updating unit tests and added missing endpoints

* Add missing credential check

* Minor unit test fixes

* fix minor linter issue

* add snaphot test unit test

* Fix on update checksum and documentation update

* update exchange, add UpdateOrderExecutionLimits, and update documentation

* Minor fix on tickers fetching

* Minor websocket fix and smaill unit tests

* Minor websocket and naming fixes

* uncomment default channels

* Fix type and unit test issues

* websocket channels and data handling update

* Update Advanced-Algo websocket handling and minor fixes

* documentation and minor code fixes

* Fix name changes

* documentation contribution update

* intervalToString method update

* fix exchange_wrapper_standard tests

* Fix minor issues based on exchange_wrapper_standards_test

* Fix wrapper extended candlestick check

* websocket orders fetching error check method update

* Exchange name check and change

* docs: Add missing contributors

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Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

engine/engine_test.go

@@ -355,8 +355,7 @@ func TestSettingsPrint(t *testing.T) {
 }
 
 var unsupportedDefaultConfigExchanges = []string{
-	"okcoin international", // due to unsupported API
-	"itbit",                // due to unsupported API
+	"itbit", // due to unsupported API
 }
 
 func TestGetDefaultConfigurations(t *testing.T) {