[Feature Request]: Show last update date timestamp

[theletterf]

Prerequisites

• I have searched existing issues to ensure this feature hasn't already been requested
• I have tested using the latest version of docs-builder

What problem are you trying to solve?

It would be good to show the last update date of each document, based on Git timestamps. For example:

Proposed Solution

• Collect the git history at build.
• Produce the timestamp for each built document based on the git timestamp.

Not sure how this would work for reference docs though.

Examples and Research

MkDocs and others do it based on git information: https://squidfunk.github.io/mkdocs-material/setup/adding-a-git-repository/#document-dates

Alternative Solutions

No response

Additional Context

No response

How important is this feature to you?

Nice to have

[theletterf]

+CC @bmorelli25 @alaudazzi

[KOTungseth]

Prior art (but for AsciiDoc)

Seal of freshness

Notes I've collected along the way

Definitions:

• Last edited date: Ran through linting (probably Acrolinx and received 80% proficiency score)
• Last validated date: Reviewed by SME, QA, or Dev that created the feature/capability

Possible process:

• Checklist for PR validation
• Create schedule for making sure docs are not stale
• How often Docs need to be validated? Run a search?

Open questions:

• If we don't retroactively implement changes, would it be weird to have these dates at the top of some docs, but not all?
• Automatically add via v3 or rely on authors to add?

[reakaleek]

Related #1127