Autogenerate roadmap for Verify & Release

This is based on generate_direction since both direction and vision items are important here, I think. I added a badge for Product Vision items so you can see the difference, where that's the case - let me know if you think this is too much noise. I also added the year to the category headings since we're looking out further now. Most of my code changes are about getting the direction content to generate for just one stage.

generate_direction could be refactored to be a little more efficient now that it's being called more than once, but thanks to the label filter it's not too slow for the additional calls and I don't think this is urgent.

Sadly, my emoji stickers everywhere are lost but I can find another way to communicate that thread.

Screenshots

Testing Status

• Can run direction.rb locally
• File cache re-enabled (!15614 (b6957d95))
• Direction page itself still looks correct (https://jlenny-roadmapautogen.about.gitlab.com/direction/)
• Roadmap for Verify is correct (https://jlenny-roadmapautogen.about.gitlab.com/direction/verify/)
• Roadmap for Release is correct (https://jlenny-roadmapautogen.about.gitlab.com/direction/release/)