Refactor API classes to use dependency injection pattern

[c-w]

Resolves #59

Also:

• Move services to single file

• Refactor actions to dependency injection pattern

• Increase test coverage

• Ensure that paths can be resolved

• Fix Connexion swagger UI

• Fix celery command

• Move to white-list for dockerignore

• Update prod dependencies

• Fix IDEA shell inspections

• Exclude integration code from coverage report

[codecov-io]

Codecov Report

Merging #85 into master will increase coverage by 5.02%.
The diff coverage is 94.83%.

@@            Coverage Diff             @@
##           master      #85      +/-   ##
==========================================
+ Coverage   88.38%   93.41%   +5.02%     
==========================================
  Files          21       14       -7     
  Lines         732      668      -64     
==========================================
- Hits          647      624      -23     
+ Misses         85       44      -41

Impacted Files	Coverage Δ
opwen_email_server/constants/events.py	100% <ø> (ø)
opwen_email_server/services/sendgrid.py	80.72% <ø> (+14.7%)	⬆️
opwen_email_server/constants/azure.py	100% <ø> (ø)
opwen_email_server/constants/queues.py	0% <0%> (ø)
opwen_email_server/utils/serialization.py	100% <100%> (ø)	⬆️
opwen_email_server/services/storage.py	97.74% <100%> (+0.16%)	⬆️
opwen_email_server/actions.py	96.32% <96.32%> (ø)
opwen_email_server/utils/email_parser.py	93.66% <0%> (-0.71%)	⬇️
... and 1 more

---

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 668c58d...87a0556. Read the comment docs.