Retire try.html and create new dev + prod builds (#1194)

- Followup from #1163
- Retire try.html
- Separate build config for dev and production
    - Move config for badge examples into the JS build
- Move the prod transform into npm scripts
    - In the future this could be handled using a bundler plugin
- make website builds production build as before
- Run the production build in CI to make sure it’s working
- Build the frontend on Heroku

shields.example.env

@@ -1,7 +1,7 @@
 # Base URL for redirects etc.
 BASE_URL=http://localhost:8080
 # Where your homepage is
-INFOSITE=http://localhost:8080/try.html
+INFOSITE=http://localhost:8080/
 
 # GitHub settings
 GITHUB_URL=https://api.github.com