Update PMD config to use categories
Update PMD config to use categories

See https://github.com/btkelly/gnag/issues/214

Strategy for migration was as follows:

- Include all new categories of Java rules
- Explicitly exclude the same rules as before

This may result in the collection of rules changing slightly as
some categories include rules from previously unused rulesets.

btkelly/gnag,btkelly/gnag,btkelly/gnag