Issue #2107483 by StephaneQ: Make basic_auth() module and http_basic() auth setting consistent.

...l/Core/Authentication/AuthenticationProviderInterface.php

core/modules/basic_auth/basic_auth.services.yml

...b/Drupal/basic_auth/Authentication/Provider/BasicAuth.php

.../Drupal/basic_auth/Tests/Authentication/BasicAuthTest.php

core/modules/rest/config/rest.settings.yml

core/modules/rest/lib/Drupal/rest/Tests/AuthTest.php

...sts/modules/router_test_directory/router_test.routing.yml