codebase: Cleanup various things (#1935)

* codebase: Rid base64/hex to string common funcs

* codebase: Rid local scope variable usage and other improvements

* codebase: Refactor currency pair usage across multiple exchanges

- Updated HitBTC tests to use the new currency pair format.
- Modified Kraken futures types to use currency.Pair instead of string for Symbol.
- Adjusted Kraken wrapper methods to handle currency pairs correctly.
- Refined OKX tests and types to utilize currency.Pair for instrument IDs.
- Enhanced Poloniex tests to consistently use predefined currency pairs.
- Streamlined order and orderbook tests to replace string pairs with currency.NewBTCUSD().
- Improved Yobit tests to utilize a standardized currency pair format.
- Updated validator wrapper to use currency pairs directly instead of string conversions.

* codebase: Use types.Number where possible

* refactor: update PayoutFee type to types.Number for consistency

* Refactor: Remove crypto functions to use standard library and other minor changes

- Removed custom crypto functions for SHA256, SHA512, and MD5 from the common/crypto package.
- Replaced usages of removed functions with standard library implementations in various files including:
  - cmd/websocket_client/main.go
  - engine/apiserver.go
  - exchanges/kraken/kraken.go
  - exchanges/lbank/lbank.go
  - exchanges/okx/okx_business_websocket.go
  - exchanges/kucoin/kucoin_websocket.go
  - gctscript/vm/vm.go
- Updated tests to reflect changes in the crypto functions.
- Renamed several functions for clarity, particularly in the context of order book updates across multiple exchanges.

* refactor: replace assert with require for consistency in test assertions

* refactor: Improve Binance futures candlestick test, standardise orderbook update function names and improve test parallelism

* refactor: Replace require.Len with require.Equal for better output in TestGetFuturesKlineData

cmd/websocket_client/main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"log"
@@ -10,7 +12,6 @@ import (
 
 	gws "github.com/gorilla/websocket"
 	"github.com/thrasher-corp/gocryptotrader/common"
-	"github.com/thrasher-corp/gocryptotrader/common/crypto"
 	"github.com/thrasher-corp/gocryptotrader/config"
 	"github.com/thrasher-corp/gocryptotrader/encoding/json"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/asset"
@@ -99,18 +100,13 @@ func main() {
 	resp.Body.Close()
 	log.Println("Connected to websocket!")
 
-	hash, err := crypto.GetSHA256([]byte(cfg.RemoteControl.Password))
-	if err != nil {
-		log.Println("Unable to generate SHA256 hash from remote control password:", err)
-		return
-	}
-
 	log.Println("Authenticating..")
-	var wsResp WebsocketEventResponse
+	shasum := sha256.Sum256([]byte(cfg.RemoteControl.Password))
 	reqData := WebsocketAuth{
 		Username: cfg.RemoteControl.Username,
-		Password: crypto.HexEncodeToString(hash),
+		Password: hex.EncodeToString(shasum[:]),
 	}
+	var wsResp WebsocketEventResponse
 	err = SendWebsocketEvent("auth", reqData, &wsResp)
 	if err != nil {
 		log.Fatal(err)