Add Kingsoft Cloud object storage policy to solve the cross-domain and friendly file name incompatibility problem of s3 compatible storage policy. (#2665)

* 新增金山云对象存储策略，解决s3兼容存储策略的跨域及友好文件名不兼容问题

* fix bug&add download Expire time args

* Handling of expiration times when they may be empty

inventory/types/types.go

@@ -255,6 +255,7 @@ const (
 	PolicyTypeOss    = "oss"
 	PolicyTypeCos    = "cos"
 	PolicyTypeS3     = "s3"
+	PolicyTypeKs3    = "ks3"
 	PolicyTypeOd     = "onedrive"
 	PolicyTypeRemote = "remote"
 	PolicyTypeObs    = "obs"