refactor: reorganize Application layer into folder structure

src/GreenHome.Application/Interfaces/IDeviceService.cs

@@ -0,0 +1,10 @@
+namespace GreenHome.Application;
+
+public interface IDeviceService
+{
+    Task<int> AddDeviceAsync(DeviceDto dto, CancellationToken cancellationToken);
+    Task<IReadOnlyList<DeviceDto>> ListAsync(CancellationToken cancellationToken);
+    Task<DeviceDto> GetDeviceId(string deviceName, CancellationToken cancellationToken);
+    Task<IReadOnlyList<DeviceDto>> GetUserDevicesAsync(int userId, CancellationToken cancellationToken);
+    Task<PagedResult<DeviceDto>> GetDevicesAsync(DeviceFilter filter, CancellationToken cancellationToken);
+}