✨(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- Helm sources are outdated.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/backend/core/api/permissions.py

@@ -0,0 +1,36 @@
+"""Permission handlers for the impress core app."""
+from rest_framework import permissions
+
+ACTION_FOR_METHOD_TO_PERMISSION = {
+    "versions_detail": {"DELETE": "versions_destroy", "GET": "versions_retrieve"}
+}
+
+
+class IsAuthenticated(permissions.BasePermission):
+    """
+    Allows access only to authenticated users. Alternative method checking the presence
+    of the auth token to avoid hitting the database.
+    """
+
+    def has_permission(self, request, view):
+        return bool(request.auth) or request.user.is_authenticated
+
+
+class IsAuthenticatedOrSafe(IsAuthenticated):
+    """Allows access to authenticated users (or anonymous users but only on safe methods)."""
+
+    def has_permission(self, request, view):
+        if request.method in permissions.SAFE_METHODS:
+            return True
+        return super().has_permission(request, view)
+
+
+class IsSelf(IsAuthenticated):
+    """
+    Allows access only to authenticated users. Alternative method checking the presence
+    of the auth token to avoid hitting the database.
+    """
+
+    def has_object_permission(self, request, view, obj):
+        """Write permissions are only allowed to the user itself."""
+        return obj == request.user