Support generating rss feeds via xpath

[JamYiz]

Clear and concise description of the problem

The limitations of using CSS selectors are too great, and web pages that are not standard enough cannot generate good feeds.

Suggested solution

Support generating rss feeds via xpath

Alternative

No response

Additional context

No response

Validations

• [x] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.
• [x] This issue is valid

[linear[bot]]

FOL-959 Support generating rss feeds via xpath