Use UBI base image for multi-arch

[cfilleke]

the base image used to build the Mannequin workload fabric8/java-jboss-openjdk8-jdk is not maintained for other architectures besides x86.

If https://github.com/RedHatPerf/mannequin/blob/master/src/main/docker/Dockerfile.jvm is changed to read:

FROM registry.access.redhat.com/ubi8/ubi:latest
RUN dnf -y update && dnf -y install java-1.8.0-openjdk-devel
ENV JAVA_OPTIONS=-Dquarkus.http.host=0.0.0.0
COPY target/lib/* /deployments/lib/
COPY target/*-runner.jar /deployments/app.jar
COPY ./java-runner.sh /deployments/java-runner.sh
ENTRYPOINT [ "/deployments/java-runner.sh" ]

and java-runner.sh is set to

#!/usr/bin/bash

java -cp target/lib/* -jar target/*-runner.jar

the mannequin image will build cleanly on IBM Z & Power as well as x86. Probably ARM as well.