Issue #1696660 by fubhy, xjm, fago, webflo: Added an entity access API for single entity access.

core/includes/entity.inc

core/lib/Drupal/Core/Entity/Entity.php

core/lib/Drupal/Core/Entity/EntityAccessController.php

...ib/Drupal/Core/Entity/EntityAccessControllerInterface.php

core/lib/Drupal/Core/Entity/EntityManager.php

core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php

core/lib/Drupal/Core/Entity/Field/Type/Field.php

core/lib/Drupal/Core/TypedData/AccessibleInterface.php

...ystem/lib/Drupal/system/Tests/Entity/EntityAccessTest.php

...dules/system/tests/modules/entity_test/entity_test.module

...est/lib/Drupal/entity_test/EntityTestAccessController.php

.../lib/Drupal/entity_test/Plugin/Core/Entity/EntityTest.php

core/modules/views/views_ui/lib/Drupal/views_ui/ViewUI.php