* added release.yml copied from Planetiler
* added build-release.sh copied from Planetiler
* release job adjusted for planetiler-openmaptiles
* fixed path to target/*with-deps.jar
* GPG private key skip[ped, since we're not going to publish to maven central
* removed -Pflatten, since (unlike planetiler) this is not multi-module repo
* removed settings for pushing to maven central, we're not doing that here
* push-release.sh replaced with Docker push and artifact upload (line in snapshot.yml)
