How to run/deploy devilbox (Docker image) docker-compose on GCP without a Dockerfile?
Firstly, docker-compose is is a tool for defining and running multi-container Docker applications. (https://docs.docker.com/compose/).
Dockerfile is single-container, if you want to run multi-containers on GKE you should convert docker-compose to kubernetes deployment.

You can manually convert or use http://kompose.io/ to convert automatically.