Migrate Ultimate to Java 21 and update framework components

[bahnwaerter]

This series of patches migrates Ultimate to Java 21 and updates the framework components to the following versions:

• Eclipse 4.32
• Eclipse CDT 11.6
• Jetty 12

The patches also improve the build process by unifying build automation for Ant tasks in Eclipse and Maven builds. Specific Ant settings and the installation of the Tycho plugin in the Eclipse IDE are no longer required for building Ultimate. In addition, dependencies from the P2 repositories are resolved automatically. Therefore, only one PDE target platform file is now required for all supported target architectures.