🚀 Feature: Add an opt-in Block adding create-typescript-app as a devDependency with automatic templating upgrades

[JoshuaKGoldberg]

Bug Report Checklist

• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Overview

This is kind of a culmination of #1181: now that create-typescript-app is built on Bingo, I want to formalize the flow of downstream repositories automatically updating to newer versions of templating tooling. This will mean that anybody with many repos on CTA (me!) won't have to take manual actions to roll out new template features to their repos.

My initial idea for the flow is an opt-in Block that adds:

1. "create-typescript-app" as a package.json devDependency
2. A CI action triggered when Renovate updates create-typescript-app to:

• Run pnpx create-typescript-app
• Check in all changes to that branch

...or something automated like that.

The end goal is that repos which opt into this should be kept up-to-date with the latest CTA template always, fully automated.

Additional Info

Renovate's postUpgradeTasks could be used for the CI, except they're only supported for self-hosted Renovate instances.

🎁