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

exchanges/deribit/deribit.go

@@ -2,6 +2,7 @@ package deribit
 
 import (
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"net/http"
@@ -2206,22 +2207,20 @@ func (d *Deribit) SendHTTPAuthRequest(ctx context.Context, ep exchange.URL, epl
 	if err != nil {
 		return err
 	}
-	reqDataStr := method + "\n" + deribitAPIVersion + "/" + common.EncodeURLValues(path, params) + "\n" + "\n"
-	n := d.Requester.GetNonce(nonce.UnixNano).String()
-	strTS := strconv.FormatInt(time.Now().UnixMilli(), 10)
-	str2Sign := strTS + "\n" + n + "\n" + reqDataStr
 	creds, err := d.GetCredentials(ctx)
 	if err != nil {
 		return fmt.Errorf("%w, %v", request.ErrAuthRequestFailed, err)
 	}
-	hmac, err := crypto.GetHMAC(crypto.HashSHA256,
-		[]byte(str2Sign),
-		[]byte(creds.Secret))
+	req := method + "\n" + deribitAPIVersion + "/" + common.EncodeURLValues(path, params) + "\n\n"
+	n := d.Requester.GetNonce(nonce.UnixNano).String()
+	ts := strconv.FormatInt(time.Now().UnixMilli(), 10)
+	tsReq := []byte(ts + "\n" + n + "\n" + req)
+	hmac, err := crypto.GetHMAC(crypto.HashSHA256, tsReq, []byte(creds.Secret))
 	if err != nil {
 		return err
 	}
 	headers := make(map[string]string)
-	headerString := "deri-hmac-sha256 id=" + creds.Key + ",ts=" + strTS + ",sig=" + crypto.HexEncodeToString(hmac) + ",nonce=" + n
+	headerString := "deri-hmac-sha256 id=" + creds.Key + ",ts=" + ts + ",sig=" + hex.EncodeToString(hmac) + ",nonce=" + n
 	headers["Authorization"] = headerString
 	headers["Content-Type"] = "application/json"
 	var tempData struct {

exchanges/deribit/deribit_websocket.go

@@ -2,6 +2,7 @@ package deribit
 
 import (
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"net/http"
@@ -155,9 +156,7 @@ func (d *Deribit) wsLogin(ctx context.Context) error {
 	n := d.Requester.GetNonce(nonce.UnixNano).String()
 	strTS := strconv.FormatInt(time.Now().UnixMilli(), 10)
 	str2Sign := strTS + "\n" + n + "\n"
-	hmac, err := crypto.GetHMAC(crypto.HashSHA256,
-		[]byte(str2Sign),
-		[]byte(creds.Secret))
+	hmac, err := crypto.GetHMAC(crypto.HashSHA256, []byte(str2Sign), []byte(creds.Secret))
 	if err != nil {
 		return err
 	}
@@ -171,7 +170,7 @@ func (d *Deribit) wsLogin(ctx context.Context) error {
 			"client_id":  creds.Key,
 			"timestamp":  strTS,
 			"nonce":      n,
-			"signature":  crypto.HexEncodeToString(hmac),
+			"signature":  hex.EncodeToString(hmac),
 		},
 	}
 	resp, err := d.Websocket.Conn.SendMessageReturnResponse(context.TODO(), request.Unset, req.ID, req)