Revert the new configuration option for the core:PHP authproc. Since we need...

Revert the new configuration option for the core:PHP authproc. Since we need to serialize authprocs and SP metadata in the state array, and closures are not serializable, it doesn't work. We could create a new module with this, adding a dependency on opis/closure 2.0.* or equivalent, to be able to serialize closures.