Schema augmentation refactor

[michaeldgraham]

Hello everyone!

This PR has been in the works for a while, and I've appreciated your patience. It almost entirely rewrites the augmentation process and is meant to only replicate current behavior. Still, as a result of new design, there are a few changes that might go noticed:

1. Types are generated in a different order. Augmentation testing has been updated to compare schemas regardless of ordering differences.
2. All type extensions are now persisted.
3. Default @relation type directives are no longer generated (an undocumented behavior...), although default relationship name arguments still are.

It is my hope that this design will enable a smoother development of various bug fixes and features that depend upon the augmentation process. I would love any feedback you might have! 🙂🚀

[codecov-io]

Codecov Report

Merging #322 into master will increase coverage by 0.85%.
The diff coverage is 97.88%.

@@            Coverage Diff             @@
##           master     #322      +/-   ##
==========================================
+ Coverage    95.4%   96.25%   +0.85%     
==========================================
  Files          10       23      +13     
  Lines        2350     2565     +215     
==========================================
+ Hits         2242     2469     +227     
+ Misses        108       96      -12

Impacted Files	Coverage Δ
src/augment/ast.js	100% <100%> (ø)
src/augment/input-values.js	100% <100%> (ø)
src/augment/types/node/node.js	100% <100%> (ø)
src/augment/types/node/query.js	100% <100%> (ø)
src/augment/types/node/mutation.js	100% <100%> (ø)
src/augment/types/types.js	100% <100%> (ø)
src/translate.js	98.64% <100%> (ø)	⬆️
src/utils.js	94.59% <100%> (+1.37%)	⬆️
src/augment/fields.js	100% <100%> (ø)
src/auth.js	72% <100%> (-6.73%)	⬇️
... and 23 more

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