Update Java Version

[Kathrin-Huber]

Description

Due to security reasons as well as questions of support it is necessary to update the Java Version.
As Java 11 is a Version with Long time Support, it is recommended to use it for further development.
As a sideeffect, the Tomcat version needs to be updated to be compatible.
Furthermore all dependencies needs to be checked for new versions to keep them compatible.

TODO:

• Make source code Java 11 compatible
• change Java version in required places (e.g. pom)
• check dependencies for newer versions and update them
• update tomcat to Version 9
• replace or remove tomcat-maven-plugin

Estimated Costs and Complexity

This is a mid-range project for about 7-9 PT

Related Issues

• Update Java (and maybe Tomcat) version  #4106
• Update tomcat #2929

[solth]

* update tomcat to Version 8

Since we already verified in several installations that the most current version of Kitodo.Production 3.x runs on Tomcat 9 I would suggest to update to that version instead.

[stefanCCS]

Good idea, lets do it!