exchanges: Refactor time handling and other minor improvements (#1948)

* exchanges: Refactor time handling and other minor improvements

- Updated Kraken wrapper to utilise new time handling methods.
- Simplified Kucoin types by removing unnecessary structures and using direct JSON unmarshalling.
- Improved websocket handling in Kucoin to directly parse candlestick data.
- Modified Lbank types to use the new time representation.
- Adjusted Poloniex wrapper and types to utilise the new time handling.
- Updated Yobit types and wrapper to reflect changes in time representation.
- Introduced DateTime type for better handling of specific time formats.
- Added tests for DateTime unmarshalling to ensure correctness.
- Rid UTC().Unix and UTC().UnixMilli as it's not needed
- Correct Huobi timestamp usage for some endpoints.
- Rid RFC3339 time parsing since Go does that automatically.

* exchanges: Refactor JSON unmarshalling for various types and improve test coverage

* linter: Update error message in TestGetKlines

* refactor: Simplify JSON unmarshalling in MovementHistory and improve test assertions in GetKlines

* refactor: Improve JSON unmarshalling for channel name and clarify comment in wsProcessOpenOrders

* refactor: Update time handling in Huobi types to use types.Time for createdAt fields and relax GetLiquidationOrders test

* refactor: Move wsTicker, wsSpread, wsTrades, and wsCandle types to kraken_types.go for better organistion

* refactor: Add validation for underlying parameter in GetExpirationTime and update tests

exchanges/alphapoint/alphapoint_wrapper.go

@@ -357,8 +357,7 @@ func (a *Alphapoint) GetActiveOrders(ctx context.Context, req *order.MultiOrderR
 			if resp[x].OpenOrders[y].State != 1 {
 				continue
 			}
-
-			orderDetail := order.Detail{
+			orders = append(orders, order.Detail{
 				Amount:          resp[x].OpenOrders[y].QtyTotal,
 				Exchange:        a.Name,
 				ExecutedAmount:  resp[x].OpenOrders[y].QtyTotal - resp[x].OpenOrders[y].QtyRemaining,
@@ -366,12 +365,10 @@ func (a *Alphapoint) GetActiveOrders(ctx context.Context, req *order.MultiOrderR
 				OrderID:         strconv.FormatInt(int64(resp[x].OpenOrders[y].ServerOrderID), 10),
 				Price:           resp[x].OpenOrders[y].Price,
 				RemainingAmount: resp[x].OpenOrders[y].QtyRemaining,
-			}
-
-			orderDetail.Side = orderSideMap[resp[x].OpenOrders[y].Side]
-			orderDetail.Date = time.Unix(resp[x].OpenOrders[y].ReceiveTime, 0)
-			orderDetail.Type = orderTypeMap[resp[x].OpenOrders[y].OrderType]
-			orders = append(orders, orderDetail)
+				Side:            orderSideMap[resp[x].OpenOrders[y].Side],
+				Date:            resp[x].OpenOrders[y].ReceiveTime.Time(),
+				Type:            orderTypeMap[resp[x].OpenOrders[y].OrderType],
+			})
 		}
 	}
 	return req.Filter(a.Name, orders), nil
@@ -398,7 +395,7 @@ func (a *Alphapoint) GetOrderHistory(ctx context.Context, req *order.MultiOrderR
 				continue
 			}
 
-			orderDetail := order.Detail{
+			orders = append(orders, order.Detail{
 				Amount:          resp[x].OpenOrders[y].QtyTotal,
 				AccountID:       strconv.FormatInt(int64(resp[x].OpenOrders[y].AccountID), 10),
 				Exchange:        a.Name,
@@ -406,12 +403,10 @@ func (a *Alphapoint) GetOrderHistory(ctx context.Context, req *order.MultiOrderR
 				OrderID:         strconv.FormatInt(int64(resp[x].OpenOrders[y].ServerOrderID), 10),
 				Price:           resp[x].OpenOrders[y].Price,
 				RemainingAmount: resp[x].OpenOrders[y].QtyRemaining,
-			}
-
-			orderDetail.Side = orderSideMap[resp[x].OpenOrders[y].Side]
-			orderDetail.Date = time.Unix(resp[x].OpenOrders[y].ReceiveTime, 0)
-			orderDetail.Type = orderTypeMap[resp[x].OpenOrders[y].OrderType]
-			orders = append(orders, orderDetail)
+				Side:            orderSideMap[resp[x].OpenOrders[y].Side],
+				Date:            resp[x].OpenOrders[y].ReceiveTime.Time(),
+				Type:            orderTypeMap[resp[x].OpenOrders[y].OrderType],
+			})
 		}
 	}
 	return req.Filter(a.Name, orders), nil