Enhancement/issue 278 graphql plugin

[thescientist13]

Related Issue

resolves #278

Summary of Changes

1. Created graphql package, and moved data/ folder from cli package
2. Upgraded <app-header> and <app-shelf> components to use client
3. Upgraded to Apollo 3 *
4. Found a bug with rollup load handling for serving custom resources
5. Restored test cases / unit test, moved under plugin-graphql and improved to cover all query cases

TODOs

1. Enable Unit Tests / Specs
2. Documentation
3. Review status of reduce duplicate fetches for cache.json by storing in client.js memory #347 and data client is not rehydrating from existing WINDOW.APOLLO_STATE on initial load #349
4. @apollo/client support in client.js (see thoughts below) - added as a Roadmap to 1.0 Tracking item
5. clean up example code / TODOs / commented out code
6. Track open items

Thoughts / Questions

Apollo Client

There were a number of issues / hacks / workarounds I bumped into while trying to use @apollo/client in client.js so I have put that work into a branch for now, but will still try and kick the tires for a bit longer

• Due to one of @apollo/client's dependencies still being CommonJS (fast-json-stable-stringify), including our plugin-import-commonjs was required
• Although ESM, graphql/language/parser.mjs doesn't provide a default export, which I had to handle using intercept
• There is an odd quirk with ts-invariant dependency needing to be resolved within @apollo/client package's node_modules
• Had to stop using getQueryHash for the time being since Apollo isn't available on the client now

---

Ultimately landed on this bug, same thing happened in apollo-client. 😞

Refactoring / Tracking Items

All tracked under Road to 1.0 list in #418

1. need to ensure a clear distinction between when file extensions are / aren't needed when using import as the spec says they should always be there but for now, will make it so node_modules can be bare, and can make an issue to add support for bare module specifier as a plugin
2. should create implement shared package.json dependency walker for importMaps like in plugin-babel / regenerator-runtime
3. Currently need to have distinction between common and server client's until we can get to node v14 where we can use import on NodeJS code
4. Should really implement server.stop handling on process end
5. try and avoid need for createCache round-robin 🐦

[thescientist13]

Took a little time to look into #347 and #349 to see if there were any quick wins but there as the new baseline is specifically targeted towards SSG, there would at least need to be an MPA (or SPA) option in place in order to be able to keep existing data in memory, since as of right now, every page is a hard load. Will move those two issues to deferred and will plan to schedule them for the next Project.

[thescientist13]

Was hoping closing and reopening would trigger a Netlify build a la #489 but didn't seem to happen. Maybe because no change in git hash?