Move away from Django dev WSGI server

[joshgamache]

https://github.com/orgs/bcgov/projects/122/views/2?pane=issue&itemId=49835390

Dev Story: I want to replace the Django WSGI server with Gunicorn because it is not intended to be used in production and this will help me to enhance the performance, security, and scalability of our Django application in the production environment.

Acceptance criteria:

1. Backend server runs on Gunicorn rather than Django-dev.

Consideration and notes

• See cas-reg #513 and the PR https://github.com/bcgov/cas-registration/pull/575 for Cas-reg context.

Tasks

• [ ] Add Gunicorn to poetry-python dependencies
• [ ] Update backend dockerfile to run Gunicorn server instead of python manage.py runserver
• [ ] Update django settings to differentiate debug mode

[joshgamache]

Check https://github.com/bcgov/cas-registration/pull/689 for additional changes to make when taking care of this debt.

[pbastia]

Closing this! With the monorepo, the single backend already uses gunicorn. cc @patriciarussellCAS @joshgamache