✨ feat: added /starters page

[JoshuaKGoldberg]

PR Checklist

• [x] Addresses an existing open issue: fixes #1
• [x] That issue was marked as accepting prs
• [x] Steps in CONTRIBUTING.md were taken

Overview

Adds an initial https://learningtypescript.com/starters with four projects. Also fixes a few issue template link typos, heh.

I'll push-to-main the right URL for the button once I can get the autogenerated URL from GitHub...