Expose front matter (meta data) to the page?

[Fil]

Exposing meta data to the page could help in many scenarios. For a concrete example, suppose that I want to show an author's name in a page.

If I defined it in the front matter as

---
author: Fil
date: 2024-03-11
keywords: [ spam, ham ]
---

and could somehow reuse these in the page with something like ${meta.author}, it would help a lot when organizing a complex website.

I would like it to be also available for SSR (#931).

Related: #56

(Initially a comment in #178)