Add a module info

[bowbahdoe]

This adds a full module-info descriptor for users of Java 9+. It is packaged as a multi-release Jar so there should be no breakage.

This is needed for

• Using jlink when this appears as a transitive or direct dependency.
• Publishing an artifact which depends on this artifact. The social convention is without a module-info or Automatic-Module-Name that module names are considered unstable.