This epic is about dropping target compatibility towards Java 8. Target Magnolia version will require Java 11 as minimum runtime environment (knowing Java 17, the next LTS is already out anyway).

• Bump module's target java-version to Java 11 or 17 straight
• Ensure Core's test-jar is usable on Java 11–17 (Repo test-cases & MVHTests)

In parallel with this change, we aim to generalize a few things with how we build/release modules:

• Permanent x.y SNAPSHOTs ( on p13n, test-framework)
• Consider Keep a Changelog & SemVer ( on sso, test-framework, parent-poms)

Create release/6.2 branches (and respective release branches in modules)
+/- Automatic branch merges (DEV-1720)

See also BUILD-303 for prior work on going beyond Java 8.