Implement contrib Entity API's query access handler

Problem/Motivation

The contrib Entity API's query access handler allows custom entity types to filter out inaccessible entities on database level. This handler is being automatically included on entity queries and views configurations.

Remaining tasks

Implement the query access handler for Storage entities.

User interface changes

Views lists might exclude inaccessible rows beforehand.

API changes

Query access handler adds further SQL conditions to entity queries and views.
Existing entity queries will thus exclude inaccessible rows, unless $entity_query->accessCheck(FALSE) is explicitly set.