Feature/issue 954 puppeteer plugin

[thescientist13]

Related Issue

resolves #954

Summary of Changes

1. Moved puppeteer to be a (customUrl) based prerender only plugin package
2. Made WCC default prerenderer
3. Upgraded puppeteer version
4. Updated tests cases that depended directly on prerendering (had to bump coverage down due to 1% drop)
5. Update site documentation accordingly

Note: there will be some lingering cross dependencies for GraphQL and Import Plugins on Puppeteer plugin for pre-rendering support until #878 / #952 have been addressed

TODO

1. Fix Windows specs (index pages not rendering)
2. former JS <> HTML inline prerender dependent specs not working now? (see xit in puppeteer plugin)
3. Documentation (website / package README)
4. Sweep CLI / Puppeteer package.json file for accuracy
5. Upgrade to latest versions of WCC
6. Plugin Import JSON export is wrong (also fix spellings of Uaer and @greenwod) - need to make an issue - Import CommonJS plugin named export is spelled wrong 🤦 #961
7. preRenderCompilationWorker should / could run as a Promise.all?

Questions / Backlog Tracking

• Upstream Notes (WCC)
  • gracefully handle SSR of a custom element <app-header> if the dependency JS has not been found / provided) (just log a warning instead) - handle usage of unregistered custom elements wcc#25
• Get puppeteer to work in a worker and still share browser instance across workers? (nice to have) - tracked in my backlog
• Prerender in development and also be able to use customUrl in development - tracked in my backlog
• future of graphql plugin + prerendering and SSR? - deferred to Data Loading Strategies #952 / Rendering Strategies (prerender vs SSR vs CSR) #951

[thescientist13]

What's odd about the windows failure is that it the Puppeteer rendering is only broken for the home page (/ route). For example, running the serve task on Windows will exhibit the failing test cases on the home page, but About and all other pages work fine. (notice the <app-header>) 😕 🤔

Home Page

Getting Started

Some thoughts off the top of my head

• A race condition given it is the first page? Maybe I can verify if the graph.json file for it gets made correctly
• Something about paths / routes on Windows? / vs \
• Delete and downgrade Puppeteer version