render some projects when browser does not support JS

[shiftkey]

Resolves #511
Supersedes #1079

This PR improves the experience when a user visits the site without JS. This is what you currently see today:

I wanted to pick up #1079 and take it to it's logical conclusion but I had some issues with the approach chosen:

• rendering every project in the list wasn't optimal now that we're at almost at 800 projects
• the order of projects is not randomized in that way
• we lacked any sorts of stats for the projects listed (now available due to caching stats in project output on build #1346)

So what does this PR give us now when JS is disabled?

• render a randomized list of 50 projects
  • this is set at build time, so it'll regenerate each time the site publishes to GitHub Pages
• embedded stats alongside each project
  • we couldn't do this before because we hit the GitHub API directly)
• added a warning message to explain the behaviour
  • this is unstyled for now and would be great for someone else to polish

Here's a quick screenshot:

This feels like a better incremental change than what was initially proposed in #1079, and we can refine this over time based on how we feel about it.

• update comment to link to this PR
• measure overhead of including this static list of projects
• confirm or give up on excluding projects with zero open issues
• test deploy site with JS disabled
• test deploy site with JS enabled
• get tag links working or disable them for now

[shiftkey]

With this PR, we only increase the download size of the main HTML file (gzip compressed) by 5KB

Current site:

This PR:

Over in #1079 (comment) we were looking at an additional 70KB being served up to every visitor, so this feels like a great improvement.