[refactor]Move User/CloudFile/UploadFile/DownloadFile to entity package

Signed-off-by: Ethan Shan <shan0xiao0xi@gmail.com>
[Refactor]Move PullFileListTask from internal class to common class

Signed-off-by: Ethan Shan <shan0xiao0xi@gmail.com>
[Browser]Browser cloud file 50% complete

Signed-off-by: Ethan Shan <shan0xiao0xi@gmail.com>