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/binance/binance_wrapper.go

@@ -1674,12 +1674,12 @@ func (b *Binance) GetHistoricCandles(ctx context.Context, pair currency.Pair, a
 		}
 		for i := range candles {
 			timeSeries = append(timeSeries, kline.Candle{
-				Time:   candles[i].OpenTime,
-				Open:   candles[i].Open,
-				High:   candles[i].High,
-				Low:    candles[i].Low,
-				Close:  candles[i].Close,
-				Volume: candles[i].Volume,
+				Time:   candles[i].OpenTime.Time(),
+				Open:   candles[i].Open.Float64(),
+				High:   candles[i].High.Float64(),
+				Low:    candles[i].Low.Float64(),
+				Close:  candles[i].Close.Float64(),
+				Volume: candles[i].Volume.Float64(),
 			})
 		}
 	case asset.CoinMarginedFutures:
@@ -1695,12 +1695,12 @@ func (b *Binance) GetHistoricCandles(ctx context.Context, pair currency.Pair, a
 		}
 		for i := range candles {
 			timeSeries = append(timeSeries, kline.Candle{
-				Time:   candles[i].OpenTime,
-				Open:   candles[i].Open,
-				High:   candles[i].High,
-				Low:    candles[i].Low,
-				Close:  candles[i].Close,
-				Volume: candles[i].Volume,
+				Time:   candles[i].OpenTime.Time(),
+				Open:   candles[i].Open.Float64(),
+				High:   candles[i].High.Float64(),
+				Low:    candles[i].Low.Float64(),
+				Close:  candles[i].Close.Float64(),
+				Volume: candles[i].Volume.Float64(),
 			})
 		}
 	default:
@@ -1755,12 +1755,12 @@ func (b *Binance) GetHistoricCandlesExtended(ctx context.Context, pair currency.
 			}
 			for i := range candles {
 				timeSeries = append(timeSeries, kline.Candle{
-					Time:   candles[i].OpenTime,
-					Open:   candles[i].Open,
-					High:   candles[i].High,
-					Low:    candles[i].Low,
-					Close:  candles[i].Close,
-					Volume: candles[i].Volume,
+					Time:   candles[i].OpenTime.Time(),
+					Open:   candles[i].Open.Float64(),
+					High:   candles[i].High.Float64(),
+					Low:    candles[i].Low.Float64(),
+					Close:  candles[i].Close.Float64(),
+					Volume: candles[i].Volume.Float64(),
 				})
 			}
 		case asset.CoinMarginedFutures:
@@ -1776,12 +1776,12 @@ func (b *Binance) GetHistoricCandlesExtended(ctx context.Context, pair currency.
 			}
 			for i := range candles {
 				timeSeries = append(timeSeries, kline.Candle{
-					Time:   candles[i].OpenTime,
-					Open:   candles[i].Open,
-					High:   candles[i].High,
-					Low:    candles[i].Low,
-					Close:  candles[i].Close,
-					Volume: candles[i].Volume,
+					Time:   candles[i].OpenTime.Time(),
+					Open:   candles[i].Open.Float64(),
+					High:   candles[i].High.Float64(),
+					Low:    candles[i].Low.Float64(),
+					Close:  candles[i].Close.Float64(),
+					Volume: candles[i].Volume.Float64(),
 				})
 			}
 		default: