Remove redundant or unnecessary PHPMD checks.

Current behavior of PHPMD has a lot of "false violations" that are simply part of how Drupal operates (between hook parameters, long function names, and so on). It also has some redundant coding standards checks to PHPCS. This is a stab at refining the PHPMD rules to suite our purposes with Drupal. The results are far more legible.

The path to the ruleset file needs to be relative to where you run "grunt phpmd" as far as I can tell, I could not figure out a quick good trick for that, so put in a hard-coded path. Thoughts?

@arithmetric