feat: prerender plugin

[rschristian]

Largely mimics WMR's setup, as that was pretty slick, with a few minor changes:

• Can prerender into any template element, doesn't require document.body
• Will search for prerender() function in any script listed in input HTML doc, doesn't require a certain placement
  • User can specify a prerender script through the plugin options instead, if they prefer/need to
• Regex is fun, but switched off the HTML regex shenanigans for a real html parser. I'm a buzzkill, I know.

Patches for Vite's preloader were all that was needed to get the bundles working in Node. I've asked if they'd be willing to implement this upstream, but we'll see.

[rschristian]

Done just for types -- newer versions of Vite (conveniently) expose Rollup's types (import type { Rollup } from 'vite') so we can drop this in the future.

[JoviDeCroock]

Tested in JoviDeCroock/blog-portfolio#60

Seems to work well, one of my "gripes" is that all the meta/... is rendered on a single line which might not be easy to read and validate for people.

We might want to write something up about this where wmr migration has become easier and so has SSG with our preset