- Due compatibility issues with the new Spring Framework version 6.x we want to change along. This includes upgrades of JDK, dependencies and the transition from "import javax.*" to "import jakarta.*"
 Reference: https://spring.io/blog/2021/09/02/a-java-17-and-jakarta-ee-9-baseline-for-spring-framework-6
            https://github.com/spring-projects/spring-framework/wiki/What%27s-New-in-Spring-Framework-6.x

- Jakarta dependencies
  Moved dependencies from javax-* to jakarta-* packages. Transitive dependencies using still javax has been upgraded as well. This includes the following libraries:
       - jakarta.validation-api
       - jakarta.persistence
       - jakarta.servlets
       - hibernate-validator
       - spring (uses jakarta from up version 3.x)

 - JDK17
   Upgrading the current version of the JDK in order to move along the spring baseline. This upgrades the JDK from version 8 to version 17. Dependencies for having a clean build have also been upgraded:
       - jacoco
       - maven-war-plugin
       - lombok

 - TestModelClassWithLotsOfIrrelevantAnnotations
   Removing annotation @SafeHtml due to hibernate-validator API changes - Annotation not present in class path anymore.

- delete AngularJS as client example due to the fact that it works with other clients as well