change env var keys

Fix linting issues

Update CHANGELOG.md

Update CHANGELOG.md

Update CHANGELOG.md

Change CMD to entrypoint and accept --mode argument

update requirements.txt

feat: add /health endpoint

* add a new route
* add CHANGELOG.md
* Update Dockerfile
* Update tests

feat: implement app authentication | ops-2905

Add a new method, extract and re-use

* Refactor and reduce duplicacy
* Use reponse raise for status for raising HTTP Errors
* Add docstrings and improve code liniting to 10/10
* Update unit tests as per refactoring