Convert Login, Signup to function components

[imnasnainaec]

This change is 

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (51f9db2) 71.42% compared to head (a69a7b1) 82.85%.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #2777       +/-   ##
===========================================
+ Coverage   71.42%   82.85%   +11.43%     
===========================================
  Files         247       44      -203     
  Lines        9369     4533     -4836     
  Branches     1075      530      -545     
===========================================
- Hits         6692     3756     -2936     
+ Misses       2360      643     -1717     
+ Partials      317      134      -183     

Flag	Coverage Δ
backend	82.85% <ø> (+0.02%)	⬆️
frontend	?

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[jasonleenaylor]

Reviewed 6 of 11 files at r1, 13 of 13 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)

---

src/components/Login/Signup.tsx line 46 at r2 (raw file):

const defaultSignupError: SignupError = {
  [SignupField.Email]: false,

Oooh, fancy.