The idea is that we split the phpcs standard from local_codechecker into its own package which can be installed by composer.

Then we add that to the composer dev depencies of moodle. Then..

1. Developers can configure their editors to a standard relative moodle phpcs path (vendor/foo/bar)
2. The rules can be more easily versioned (and respected by cibot) - means we can start using phpcs for deprecations and so on