Migrate to Sonatype's Central Publisher Portal

[marcphilipp]

Sonatype has announced that they will sunset the OSSRH service that we're using to publish snapshots to oss.sonatype.org and releases to Maven Central. Therefore, we need to adjust our build to publish to their new Central Publisher Portal instead.

Deliverables

• Set up build to publish via Maven Central Portal #4487
• Adjust release build to use Central Publisher Portal

[marcphilipp]

Waiting for Sonatype to manually migrate the org.junit namespace to the Publisher Portal mechanism.