ZEN-4862 Adapt KZOP for maven-release-plugin

[andylowry]

Going forward, release management will use the maven-release-plugin. We'll no longer use date-time stamps as version qualifiers.

Version releases will be performed directly in master branch. PRs should never change project version.

We have disabled the release:perform goal, becuase we do deployments from RepreZen's (private) TeamCity installation. That may change in the future.

Proper sequence to move to a new release is:

• Be in clean, up-to-date master branch
• run: mvn release:prepare, specifying new release as appropriate and accepting defaults for everything else
• run mvn release:clean
• push to github