Should this be marked as unmaintained

[WilliamParker]

As discussed at oracle-samples/clara-rules#318 the clara-tools project has not been maintained (note that clara-rules is maintained, it is clara-tools that we are discussing here).

@rbrush , you suggested there that clara-tools should have some indication of this fact. I've logged this issue to track on adding such a notice so that we can close out oracle-samples/clara-rules#318.