Write a port of WP Enforcer using Smee

[stevegrunwell]

The litmus test for whether or not Smee is ready to release will be if we can successfully replace WP Enforcer with a version running atop Smee.

The WP Enforcer package should be re-written to use Smee for the underlying behavior, with the WP Enforcer package simply providing PHP_CodeSniffer and the logic around which phpcs.xml to use.