refactor: Cleaned docker orchestration and code style

[frgfm]

This PR introduces the following modifications:

• updated client documentation for something neat
• moved config files to pyproject.toml
• added black & mypy configurations
• fixed code style for the entire codebase
• updated CONTRIBUTING and README badges
• added Makefile for easier contributions
• added a CI job for PR label verification (to automate release notes)

Any feedback is welcome!

[codecov[bot]]

Codecov Report

Merging #193 (2e7ed6a) into master (2286df6) will not change coverage. The diff coverage is 88.60%.

@@           Coverage Diff           @@
##           master     #193   +/-   ##
=======================================
  Coverage   92.71%   92.71%           
=======================================
  Files          34       34           
  Lines        1208     1208           
=======================================
  Hits         1120     1120           
  Misses         88       88           

Flag	Coverage Δ
unittests	92.71% <88.60%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/app/api/crud/authorizations.py	100.00% <ø> (ø)
src/app/api/crud/base.py	98.14% <ø> (ø)
src/app/api/routes/groups.py	100.00% <ø> (ø)
src/app/db/init_db.py	37.50% <0.00%> (ø)
src/app/services/bucket/qarnot.py	50.84% <25.00%> (ø)
src/app/db/models.py	93.10% <69.23%> (ø)
src/app/api/routes/media.py	84.72% <88.88%> (ø)
src/app/api/crud/accesses.py	97.56% <100.00%> (ø)
src/app/api/crud/alerts.py	100.00% <100.00%> (ø)
src/app/api/crud/webhooks.py	100.00% <100.00%> (ø)
... and 13 more

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