Enclosure

### What feature is it?

Utilize enclosures in addition or instead of embedding media into HTML.

### What problem does this feature solve?

Console RSS clients display HTML code, without audio, video, or images; only textual content.

Enclosures are the indicators of RSS (Atom is even better due to an enhanced mechanism) for RSS clients to recognize non-textual data, such as images, videos, zip files, audio files, et cetera.

### Additional description

Related https://github.com/DIYgod/RSSHub/issues/20254

### This is not a duplicated feature request or new RSS proposal

- [x] I have searched [existing issues](https://github.com/DIYgod/RSSHub/issues) to ensure this feature has not already been requested and this is not a [new RSS proposal](https://github.com/DIYgod/RSSHub/issues/new?assignees=&labels=RSS+proposal&template=rss_request_en.yml).