Update config.js.php processor to be class based #14161
What does it do?
In #14160 I made the deprecated message a bit more useful for identifying offending processors, which immediately pointed to the config.js.php which is called on each manager request as loading the config into a JS object. So, I wrapped it into a modProcessor class to resolve that, and added a migration to remove the old processor file when running the 2.7.1 setup.
Why is it needed?
The deprecated log message on each manager request will not only get annoying fast, but as it's not very useful until #14160, this particular instance may encourage people to disable the deprecated logging preventing them from seeing other deprecated usages that need to be fixed.