Build container images via jib-maven-plugin

[hbruch]

Summary:

This PR adds jib-maven-plugin as build dependency which allows to build and publish onebusaway gtfs tools as docker images.

Note: currently, image names are build using their maven artifactId as repository names.
To build and publish them, an env variable CONTAINER_REGISTRY_NAMESPACE needs to be defined.

To build use e.g. CONTAINER_REGISTRY_NAMESPACE=mfdz mvn jib:dockerBuild, or, to build and publish to the registry CONTAINER_REGISTRY_NAMESPACE=mfdz mvn jib:build

It will build the following images (assuming current version is 4.0.1-SNAPSHOT):

mfdz/onebusaway-gtfs-merge-cli:4.0.1-SNAPSHOT
mfdz/onebusaway-gtfs-hibernate-cli:4.0.1-SNAPSHOT
mfdz/onebusaway-gtfs-transformer-cli:4.0.1-SNAPSHOT

According to jib-maven-plugin multi-module example, module-dependencies are built as reproducible builds.

[leonardehrenfried]

Thanks for this PR. I will merge this and tweak the settings a bit myself.

[leonardehrenfried]

Sorry, I don't have the permissions to publish to Github Container Registry or Dockerhub. I will have to ask so it will take a little longer.

[leonardehrenfried]

https://hub.docker.com/r/opentransitsoftwarefoundation/onebusaway-gtfs-merge-cli/tags

Can you try if the images work?