Build trusted openjdk base images (8/9, build/runtime)

[tteggel]

An automated process for...

Minimal (smithed?) images for runtime. Oracle linux based for build images.

[msgodf]

The Java 8 build image fnproject/fn-java-fdk-build:latest is based on maven:3-jdk-8-slim. The Java 8 runtime image fnproject/fn-jafa-fdk:latest is based on openjdk:8-slim.

The Java 9 build image fnproject/fn-java-fdk-build:jdk9-latest is based on maven:3-jdk-9-slim. The Java 9 runtime image fnproject/fn-jafa-fdk:jdk9-latest is based on openjdk:9-slim.

The build images are (currently) based on images from the official Dockerhub repository for Maven https://hub.docker.com/_/maven/

The runtime images are (currently) based on images from the official Dockerhub repository for OpenJDK https://hub.docker.com/_/openjdk/