Add PHP Coding Standards configuration

[lkraav]

In the spirit of themehybrid/mythic#7 it's probably time here as well?

[justintadlock]

Considering that I write about 99% of all code that goes into HC, I'm not too keen on the idea of putting together something that I don't really use. Perhaps when I've started using it more in other projects, I might want to use it more with HC. But, right now, it's extremely low on the priority list.

If I decided to move in this direction, I'd probably want to have a written set of coding standards that I follow (it's a mix of PSR-1,2 and WP). That'd give something to build a configuration file from.

[saas786]

Close this as well, unless and until its decided to have PHPCS.

[szepeviktor]

This is a useful frankenstein
https://github.com/szepeviktor/phpcs-psr-12-neutron-hybrid-ruleset

1. formatting from PSR-12
2. security from Neutron -> WPCS
3. extra benefit from Slevomat

I hope everyone will love it! 😍