add support for module service provider

[pratikpparikh]

#16

Hi @larsga,

I have added support for adding namespaced provider modules. Please review and recommend changes, once this is approved I will check-in the group-by and experimental module function as well.

Regards,
Pratik Parikh

[larsga]

Hmmmm. I don't really understand the purpose of this PR. What are "namespaced provider modules"? Why do we want it?

[pratikpparikh]

@larsga the logic that you are using for creating modules, I am calling them namespaced provider. Just a way to address them. No biggy, another thing that you will notice is that I am using a service provider which was added in JDK6+ onwards. Also at the minimum, if you don't find any other value in the PR then please look at the build.gradle change that I did which is very simple. I use JDK 10 which requires all the libraries that I use to have either the automatic module name or module-info. I added the automatic module name, in this case, to help to utilize it in JDK 9+. I would also request you to consider using the service provider so that you allow others to build the meaningful extension without having to touch the parsercontext and other core classes as they need. Hoping this explanation helps a bit about my contribution.