Use a scopeAttribute instead of a hardcoded scope for SubjectID & PairwiseID

composer.lock

docs/simplesamlphp-changelog.md

modules/core/docs/authproc_pairwiseid.md

modules/core/docs/authproc_subjectid.md

modules/core/lib/Auth/Process/PairwiseID.php

modules/core/lib/Auth/Process/SubjectID.php

tests/modules/core/lib/Auth/Process/PairwiseIDTest.php

tests/modules/core/lib/Auth/Process/SubjectIDTest.php