🧑‍💻(docker) split frontend to another file

This commit aims at improving the user experience:
- Use a dedicated `Dockerfile` for the frontend
- Run the backend and frontend in "watch"/dev mode in Docker
- Do not start all Docker instances for small tasks

bin/pylint

@@ -35,4 +35,4 @@ fi
 
 # Fix docker vs local path when project sources are mounted as a volume
 read -ra paths <<< "$(echo "${paths[@]}" | sed "s|src/backend/||g")"
-_dc_run app-dev pylint "${paths[@]}" "${args[@]}"
+_dc_run_no_deps app-dev pylint "${paths[@]}" "${args[@]}"