Enhancement/issue 575 optional prerendering

[thescientist13]

Related Issue

resolves #575

Summary of Changes

1. Renamed serialize lifecycle -> prerender
2. Added a prerender configuration option for bypassing puppeteer
3. Added test cases
4. Add documentation

At present and maybe not immediately obvious, but this feature is incompatible with using GraphQL from the client side since without running the web components, the *-cache.json files will never get created. As per #576 if we could do this entirely with HTML somehow or some sort of <query-outlet></query-outlet> that would be great? There are some options to explore for sure.

It should be noted graph.json will still exist, so anyone can still use fetch to get the same information.

That said, the site builds suuuuuuper fast without prerendering, in like 5-6s.

Thoughts / Issues To Make

1. Some possible future prerender options?
   • browser (default) - what we are doing currently
   • RenderElement - Lit's native solution
   • LitElement - as a plugin, specifically for Lit?
   • could then add an SSR "mode"
2. In this model, it would be nice to make the puppeteer dependency optional, and only install if needed. Should make an issue for that.

Added notes in #576

TODOs

1. Documentation + disclaimer and some use cases
2. Upgrade config schema ? - not needed
3. Some general refactoring to try and share logic in the build command
4. Track a discussion around "static" templating with web components - added notes in Server Side Rendering and Templating (puppeteer alternatives) #576