refactor：将DataLoaderService中的LoadAll*Async方法移到对应的管理服务中

- 将LoadAllDevicesAsync方法移到DeviceManagementService
 - 将LoadAllVariableTablesAsync方法移到VariableTableManagementService
 - 将LoadAllVariablesAsync方法移到VariableManagementService
 - 将LoadAllMenusAsync方法移到MenuManagementService
 - 将LoadAllMqttServersAsync方法移到MqttManagementService
 - 将LoadAllNlogsAsync方法移到LogManagementService
 - 更新DataLoaderService以使用管理服务提供的方法
 - 修改IDataLoaderService接口以移除这些方法
 - 保持与LoadAllTriggersAsync相同的模式
 - 遵循单一职责原则，提高代码一致性" (提交修改并添加描述性的提交信息)

DMS.Application/Services/Management/MqttManagementService.cs

@@ -233,4 +233,18 @@ public class MqttManagementService : IMqttManagementService
 
         return changedProperties;
     }
+
+    /// <summary>
+    /// 异步加载所有MQTT服务器数据到内存中。
+    /// </summary>
+    public async Task LoadAllMqttServersAsync()
+    {
+        _appStorageService.MqttServers.Clear();
+        var mqttServers = await _mqttAppService.GetAllMqttServersAsync();
+        // 加载MQTT服务器数据到内存
+        foreach (var mqttServer in mqttServers)
+        {
+            _appStorageService.MqttServers.TryAdd(mqttServer.Id, mqttServer);
+        }
+    }
 }