Add 'Automatic-Module-Name' to MANIFEST.MF to support Java 9+ modules

Our team ships libraries that work on JDK 9+ with their module system. It would be nice to have an automatic-module-name in the JAR.
http://branchandbound.net/blog/java/2017/12/automatic-module-name/
Note: This is not about modularising qpid-proton-j; this is just adding an automatic module name. I think modularising the library is another task in itself.

In our project, it shows warnings when building for JDK 11.

[WARNING] * Required filename-based automodules detected: [proton-j-0.33.2.jar]. Please don't publish this project to a public artifact repository! *