PSR-12 compliancy

A dot or a comma is quite a difference!

* Ensure getConfig* functions can only return Configuration

* Cleanup after #1189

* Deprecate Configuration::getConfigList

* Replace mock-test with actual test

Ass^2

I'm such an ass 💩

Add support for RFC6265bis SameSite cookie attribute

This reverts commit 6bcea51e.

* Allow list of entity ids to be loaded to better support idpList

Certain metadata sources, like mdq, were don't support loading all metadata which
prevented them from being used with idplist. This change adds support for allowing
metadata sources to load a list of entities, allowing MDQ to be used for idp list.