Fix Psalm-issues in the modules-directory

* 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.

* IDP configurable AuthnContextClassRef/AuthnContextComparison

* Add a few namespaces

Start migrating to SAML2 getters/setters

Extend @mapgrady's patch for simplesamlphp/simplesamlphp#498 to allow Scoping to be disabled on a per-idp basis as well as globally

The SingleSignOn endpoint is not indexed, and as such, we should prioritize HTTP-Redirect when available in order to comply with SAML2Int.

The SingleSignOn endpoint is not indexed, and as such, we should prioritize HTTP-Redirect when available in order to comply with SAML2Int.

This reverts commit ef36c5fd.

All a bit too involved right before a planned release.

Also, convert to PSR-2 where that was still lacking in these files.

Sometimes there are issues with the metadata itself (e.g metadata
expired). These issues cannot be easily determined, due to the
Exception messages being dropped. In these cases, the current 'not
found' message can be ambiguous.

This enables too the implementation of additional contact attributes, as requested in #509 to support the SIRTFI framework.