Java 9 module support

[jmesnil]

We should add support for Java 9 module for the Config API.

I propose we use the javax.config name for the module.

[kazumura]

In this case, we have to create two versions of RIs.

And I'm not clear the independent implementations must support module to pass TCK.

[struberg]

@tomas-langer can you take over? txs!

[tomas-langer]

PR added. Using javax.config as the module name. Configuration added as Automatic-Module-Name, as the current source & target are 1.8 and not sure whether we use java9 or later for compilation. Once modules are embraced, a full module-info.java should be introduced.