#211 Support Java 17 and update build

[ndoschek]

• 211 Support Java 17 and update build

  • Update to support build with Java 17
  • We will continue compling with Java 11
  • We support the two latest LTS versions 11 and 17
  • Update versions of build plugins
  • Align p2 pom.xml to currently used targetplatform repo
  • Remove includePackedArtifacts option in target-platform-configuration plugin as this is not compatible with Java versions > 14
• Update test dependencies to be able to execute with Java 17
  • Remove some dependencies from targetplatform and consume via org.eclipse.emfcloud.modelserver.tests bundle
  • Some of the newer dependencies that work with Java 17 are not available in the required version via the targetplatform, therefore we add them to the tests bundle to consume it for the p2 profile build
  • Add dependency libs to tests bundle
  • Export dependencies via tests bundle
  • Introduce MockitoUtil that replaces Mockito's internal 'FieldSetter' class (which was removed with the newer version)
• Update README, GitHub action build workflow and Jenkins build
  • Update GitHub action build workflow to build both in Java 11 and java 17
  • Jenkins still builds with java 11 (so we publish also the jar built with 11 to avoid any possible backwards compatibility issues)

Resolves https://github.com/eclipse-emfcloud/emfcloud-modelserver/issues/211

[ndoschek]

Thanks @eneufeld for the hint, as discussed I consume most dependencies from the newer orbit, except the missing javax.servlet from the former one. Regarding hamcrest, this produces a plugin clashfor the p2 build (the junit plugin still uses the prior version internally), so I added it to the test lib feature bundle. As mentioned in the comment, we will simplify the targetplatform and remove those feature plugins with the upcoming upgrades.