✨ Add email normalization and blacklist checking

[williamchong]

No description provided.

[codecov]

Codecov Report

Merging #138 into master will decrease coverage by 0.61%.
The diff coverage is 11.32%.

@@            Coverage Diff             @@
##           master     #138      +/-   ##
==========================================
- Coverage   44.06%   43.45%   -0.62%     
==========================================
  Files          65       65              
  Lines        2630     2681      +51     
==========================================
+ Hits         1159     1165       +6     
- Misses       1471     1516      +45     

Impacted Files	Coverage Δ
src/routes/users/registerLogin.js	44.57% <0.00%> (-3.17%)	⬇️
src/util/api/users/register.js	27.61% <0.00%> (-1.10%)	⬇️
src/util/api/users/index.js	42.22% <11.76%> (-10.26%)	⬇️
src/constant/index.js	100.00% <100.00%> (ø)

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