Setup CI for jdk 9+

[shroffk]

In preparation for the move the jdk 10 it is necessary to set up CI for jdk 9+ in addition to the existing jdk8

[georgweiss]

Please check the my PRs for the optional modules.

[shroffk]

In preparation for moving the epics core projects to java 10+ the CI was updated to run on open and oracle versions of java starting from 8 to 11

At the last build all problems related to the javadoc production have been resolved.
https://travis-ci.org/epics-base/epicsCoreJava/builds/433584801

The only open issue is that openjfx is no longer available for trusty. It is available for xenial and bionic distributions of ubuntu.

[shroffk]

The oracle jdk10 is no longer available for travis CI need to remove it from the travis.yml and start preparing for openjdk11