Migrate Indy to JDK11.

[whitingjr]

To make the transition to JDK11 there are changes necessary to the codebase.

These can be summarised as:

• Add module descriptor metadata
• Swap out API removed from the JRE

See the JDK11 Release Notes for details.

[whitingjr]

Swapping out the classes has been done in PR #1517

[whitingjr]

To test with JDK11 a system property needs adding. Without the property the BMUnit tests error. This will be added by the PR #1547

[whitingjr]

There is an open issue JDK-8228343 with the tooling that comes with OpenJDK11 when running in a container. Due to pid id lookups in the wrong namespace.

[whitingjr]

Function Tests also are broken. Details in #1621

[whitingjr]

At runtime JDK11 is being used. This issue will remain open until the container image uses JDK8 compiled byte-code.