Add site builder service to Docker Compose and remove obsolete scripts

- Introduced a new service `igny8_site_builder` in `docker-compose.app.yml` for site building functionality, including environment variables and volume mappings.
- Deleted several outdated scripts: `create_test_users.py`, `test_image_write_access.py`, `update_free_plan.py`, and the database file `db.sqlite3` to clean up the backend.
- Updated Django settings and URL configurations to integrate the new site builder module.

site-builder/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}