Migrate Assertions to wrapper class (#1339)

composer.json

composer.lock

lib/SimpleSAML/Auth/ProcessingChain.php

lib/SimpleSAML/Auth/ProcessingFilter.php

lib/SimpleSAML/Auth/Simple.php

lib/SimpleSAML/Auth/Source.php

lib/SimpleSAML/Auth/State.php

lib/SimpleSAML/Configuration.php

lib/SimpleSAML/Error/Assertion.php

lib/SimpleSAML/Error/AuthSource.php

lib/SimpleSAML/Error/BadRequest.php

lib/SimpleSAML/Error/Error.php

lib/SimpleSAML/Error/Exception.php

lib/SimpleSAML/Error/MetadataNotFound.php

lib/SimpleSAML/Error/NotFound.php

lib/SimpleSAML/IdP.php

lib/SimpleSAML/IdP/IFrameLogoutHandler.php

lib/SimpleSAML/IdP/TraditionalLogoutHandler.php

lib/SimpleSAML/Locale/Language.php

lib/SimpleSAML/Locale/Translate.php