Issue #556380 by deekayen, ParisLiakos, cweagans: Remove OpenID from core.

core/CHANGELOG.txt

core/MAINTAINERS.txt

core/modules/openid/config/openid.settings.yml

core/modules/openid/config/schema/openid.schema.yml

.../modules/openid/lib/Drupal/openid/Form/UserDeleteForm.php

...s/openid/lib/Drupal/openid/Tests/OpenIDFunctionalTest.php

...openid/lib/Drupal/openid/Tests/OpenIDRegistrationTest.php

core/modules/openid/lib/Drupal/openid/Tests/OpenIDTest.php

...modules/openid/lib/Drupal/openid/Tests/OpenIDTestBase.php

...pal/openid/Tests/Upgrade/OpenIDAuthmapUpgradePathTest.php

core/modules/openid/login-bg.png

core/modules/openid/openid-rtl.css

core/modules/openid/openid.api.php

core/modules/openid/openid.css

core/modules/openid/openid.inc

core/modules/openid/openid.info.yml

core/modules/openid/openid.install

core/modules/openid/openid.js

core/modules/openid/openid.module

core/modules/openid/openid.pages.inc