Content: Display the last update date on all pages

[benjaminParisel]

This enhancement comes from a request from our users. Sometimes, they read a page, and come back to read the same page another day, and they didn't know if the content is updated or not than the last time.

💡 To help users know when the content is updated, we would display the last update date.

We need to find a way to generate this metadata. If this data is not generated and needed an update for contributors, it's will never up-to-date.

⚠️

• If we put this data directly, we will face a lot of merged conflicts between versions.
• Found a way to manage this date with the "propagation" between versions. At least, we need to clarify this behavior.

Useful links:

• Reference-revision-attribute
• From Antora zulip chat Metadata from Git

Visible in the fedora docs built with Antora: https://docs.fedoraproject.org/en-US/fedora-join/

• theme repo: https://gitlab.com/fedora/docs/docs-website/ui-bundle/-/blob/main/src/partials/footer-content.hbs