Should be made more consistent with other project types. Check if org.netbeans.modules.java.api.common.project.ui can be
reused at all (might be useful for apisupport.project as well).
- should add ClassPath.BOOT as a JDK node
- add actions like Show Javadoc, Go to Source, etc.
Should also permit user to make manual source and/or Javadoc correspondences for classpath entries, though issue #160485
would be a more satisfactory and general solution.