Pages: add starter for TypeDoc

[turadg]

Closes: TypeStrong/typedoc#1485

Add a starter workflow for using the docs site generator TypeDoc (https://typedoc.org/) to publish to GitHub Pages. I adapted this from the Next.js workflow.

[github-actions]

This pull request has become stale and will be closed automatically within a period of time. Sorry about that.

[turadg]

@JamesMGreene what does it take to get this approved?

[JamesMGreene]

As much as I would love to merge in all the open source Pages starter workflows (💝), it's a bit more complicated for us than simply pressing that merge button. 😅

The unfortunate TL;DR of the situation:

• Pages starter workflows require additional effort from the Pages team to integrate so that they are fully regression tested and become detected-and-suggested workflows in the GitHub UI based on repo contents.
• I am no longer on the Pages team, so I don't have the correct permissions to push these ahead now.
• The Pages team isn't very available at the moment as they are assisting other internal teams with higher priority tasks.