Add html email templates

[lorensr]

I think it'll give a better idea to people of the existence of the option to have html if they see it printed to console or if they look at the code.

[pradel]

Good idea! can you please fix the EmailTemplateType type so the ci will pass? Thanks :)

[lorensr]

Right, Typescript! Added the type, but CI still failing:

$ prettier --list-different '**/*.{json,md,js,ts}'
packages/server/src/utils/email.ts
error An unexpected error occurred: "Command failed.
Exit code: 1
Command: sh
Arguments: -c prettier --list-different '**/*.{json,md,js,ts}'
Directory: /home/circleci/project
Output:
".

When I run the command locally, I get:

[codecov]

Codecov Report

Merging #403 into master will decrease coverage by 0.06%.
The diff coverage is 75%.

@@            Coverage Diff             @@
##           master     #403      +/-   ##
==========================================
- Coverage   95.52%   95.45%   -0.07%     
==========================================
  Files          57       57              
  Lines        1250     1254       +4     
  Branches      175      176       +1     
==========================================
+ Hits         1194     1197       +3     
- Misses         53       54       +1     
  Partials        3        3

Impacted Files	Coverage Δ
packages/server/src/accounts-server.ts	90.05% <0%> (-0.51%)	⬇️
packages/server/src/utils/email.ts	85.71% <100%> (+3.89%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e869ae3...2fe85f6. Read the comment docs.