Replace Apollo local state management

[lucasconstantino]

This is a major change. It replaces the whole state management system previously built using Apollo's internal local-state feature, with a completely rewritten GraphQL API layer which interconnects GitHub and NPM using schema stiching.

Goodies:

• Isolated API environment.
  • Easily expandable API;
  • Can boot standalone (yarn dev-api);
  • Integrates with Apollo Engine for performance lookups;
  • Can easily be moved to the server eventually;
• DataLoaders to avoid multiple calls to NPMS API, but still keeping code decoupled;
• Memoization on many parts, including on schema delegation;
• Added some tests to data-processing parts.

Tradeoffs:

• I'm no TypeScript expert, so I had to drop a bunch of generated types and type usage along the way. I intend on increment the current components with type safety on another task;

[lucasconstantino]

Fixes #31 and #34

[lucasconstantino]

I've made two videos to explain the refactoring! I might just transform the content of those videos into documentation, but may be the docs should be more focused on going forward, not backwards comparisons. Here it goes:

https://www.loom.com/share/96530313f6af42218fb1cadaf8eee974
https://www.loom.com/share/f5337d4551644f3b91b5a11a2f67d0b2