Add curl to the final Docker image

[ClementWalter]

I would like to add curl to the final image because it is convenient for pulling snapshot of the database from within the running container.

[kkovaacs]

Can't we move that initialization to a separate container? Docker compose can provide something like K8S init containers via a service_completed_successfully dependency: docker/docs#12633

That way curl could be used to populate the data volume within the https://hub.docker.com/r/curlimages/curl image.

[ClementWalter]

Yes definitely I tried to use alpine/curl to run a populate-{network}-data task before but I couldn't have this working with the docker<>ecs integration.

It's a bit frustrating because at first it seemed so easy to use but eventually very difficult to really make it work with a little more complexity in the docker-compose stack.

In any case I think you're right, so let's close this PR for now, and I may update my deployment scripts to avoid those docker<>ecs/azure integrations.