Legacy website scripts are not properly cache-busted (or bundled)

[luxaritas]

Expected Behavior

If we make a change to eg the coffeescript, the new script should be used

Current Behavior

The old version of the script will be used until the cache expires

Reproduction Steps

Make a change -> load with cache leaders -> old version still used

Environment

No response

Other information

We should probably:

• Not bother keeping the website stuff as coffeescript, and just compile it
• Instead of loading each script/asset manually in the HTML, either create a new entry point that we should load which pulls in everything or directly import into our existing entry point
• Update the script interface on the website to grab the manifest and figure out which scripts to embed from there (this interacts with Refactor/extract scripting api #749)