✨(project) Django boilerplate

This commit introduces a boilerplate inspired by https://github.com/numerique-gouv/impress.
The code has been cleaned to remove unnecessary Impress logic and dependencies.

Changes made:
- Removed Minio, WebRTC, and create bucket from the stack.
- Removed the Next.js frontend (it will be replaced by Vite).
- Cleaned up impress-specific backend logics.

The whole stack remains functional:
- All tests pass.
- Linter checks pass.
- Agent Connexion sources are already set-up.

Why clear out the code?

To adhere to the KISS principle, we aim to maintain a minimalist codebase. Cloning Impress
allowed us to quickly inherit its code quality tools and deployment configurations for staging,
pre-production, and production environments.

What’s broken?
- The tsclient is not functional anymore.
- Some make commands need to be fixed.
- Helm sources are outdated.
- Naming across the project sources are inconsistent (impress, visio, etc.)
- CI is not configured properly.

This list might be incomplete. Let's grind it.

src/helm/extra/templates/secrets.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: backend
+stringData:
+  DJANGO_SUPERUSER_EMAIL: {{ .Values.djangoSuperUserEmail }}
+  DJANGO_SUPERUSER_PASSWORD: {{ .Values.djangoSuperUserPass }}
+  DJANGO_SECRET_KEY: {{ .Values.djangoSecretKey }}
+  OIDC_RP_CLIENT_ID: {{ .Values.oidc.clientId }}
+  OIDC_RP_CLIENT_SECRET: {{ .Values.oidc.clientSecret }}