多个下载地址

### Please make sure of the following things

- [x] I have read the [documentation](https://alist.nn.ci).
- [x] I'm sure there are no duplicate issues or discussions.
- [x] I'm sure this feature is not implemented.
- [x] I'm sure it's a reasonable and popular requirement.

### Description of the feature / 需求描述

我现在是有外网和内网使用alist
但是alist的下载地址只能设置成固定的
如何才能使alist根据浏览器的host去适应下载链接呢？

### Suggested solution / 实现思路

_No response_

### Additional context / 附件

_No response_