The first thing we need to fix interplay between ${project}-maven-stage-${stream} and what is currently being done by ${project}-release-merge.

Provide a replacement job template in builder.git/jjb/releng-templates-java.yaml.

The template instantiation should provide the usual GERRIT_BRANCH, etc. values (current list is visible here: https://jenkins.opendaylight.org/releng/view/odlparent/job/odlparent-release-merge/49/parameters/). It should also only support 'maven' container without 'release file', with only 'version' provided, out of which the correct tag ('v$version') is derived.