add Dockerfile for ci build and run

deploy/ci/Dockerfile

+FROM maven:3-eclipse-temurin-17-alpine AS build
+
+# tests (in this case: including build) have to run in a non-privileged context: https://github.com/zonkyio/embedded-database-spring-test#running-tests-in-docker-does-not-work
+RUN addgroup -S -g 1000 build-user
+RUN adduser -D -S -G build-user -u 1000 -s /bin/ash build-user
+USER build-user
+
+COPY --chown=build-user . /opt/
+RUN mvn -ntp -f /opt/pom.xml clean package
+
+# based on https://gitlab.eclipse.org/eclipse/xfsc/authenticationauthorization/-/blob/main/service/Dockerfile?ref_type=heads
+FROM eclipse-temurin:17-jre-alpine
+COPY --from=build /opt/service/target/auth-service-1.1.0-SNAPSHOT.jar auth-service-1.1.0-SNAPSHOT.jar
+ENTRYPOINT ["java", "-jar", "/auth-service-1.1.0-SNAPSHOT.jar"]