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/exmo/exmo_wrapper.go

@@ -249,42 +249,16 @@ func (e *EXMO) UpdateOrderbook(ctx context.Context, p currency.Pair, assetType a
 			continue
 		}
 
-		book.Asks = make(orderbook.Tranches, len(data.Ask))
-		for y := range data.Ask {
-			var price, amount float64
-			price, err = strconv.ParseFloat(data.Ask[y][0], 64)
-			if err != nil {
-				return book, err
-			}
-
-			amount, err = strconv.ParseFloat(data.Ask[y][1], 64)
-			if err != nil {
-				return book, err
-			}
-
-			book.Asks[y] = orderbook.Tranche{
-				Price:  price,
-				Amount: amount,
-			}
+		book.Asks = make(orderbook.Tranches, len(data.Asks))
+		for y := range data.Asks {
+			book.Asks[y].Price = data.Asks[y][0].Float64()
+			book.Asks[y].Amount = data.Asks[y][1].Float64()
 		}
 
-		book.Bids = make(orderbook.Tranches, len(data.Bid))
-		for y := range data.Bid {
-			var price, amount float64
-			price, err = strconv.ParseFloat(data.Bid[y][0], 64)
-			if err != nil {
-				return book, err
-			}
-
-			amount, err = strconv.ParseFloat(data.Bid[y][1], 64)
-			if err != nil {
-				return book, err
-			}
-
-			book.Bids[y] = orderbook.Tranche{
-				Price:  price,
-				Amount: amount,
-			}
+		book.Bids = make(orderbook.Tranches, len(data.Bids))
+		for y := range data.Bids {
+			book.Bids[y].Price = data.Bids[y][0].Float64()
+			book.Bids[y].Amount = data.Bids[y][1].Float64()
 		}
 
 		err = book.Process()