Add a utility main class in common to dump the config as JSON

[jonpspri]

Create a utility main class in the 'common' library to be available in controller and invoker JARs. The class should be in Java (to minimize dependencies) and when invoked dump the current configuration in a consumable JSON format.

If the class was invoked with no overrides, the JSON produced should resemble as closely as feasible the contents of the application.conf resource(s) at compile time. The purpose of this JSON is to unify configuration across various ansible and kubernetes deployment configuration.

When the utility main class becomes available, update the ansible 'group_vars/all' and 'roles/invoker/tasks/deploy.yml' files to use it rather than (re-)setting defaults.

See PR #3412 for additonal details and discussion.