Prevent duplicate controller registrations through class-level @RequestMapping.

When we detected @BasePathAwareController and @RepositoryRestController instances, we now reject types that use @RequestMapping on the class level as doing so causes an inevitable registration of the controller with Spring MVC.

Fixes #1342, #1628, #1686, #1946.

spring-data-rest-tests/spring-data-rest-tests-jpa/src/test/java/org/springframework/data/rest/webmvc/jpa/JpaRepositoryConfig.java

@@ -59,10 +59,9 @@ public class JpaRepositoryConfig extends JpaInfrastructureConfig {
 	}
 
 	@RepositoryRestController
-	@RequestMapping("orders")
 	static class OrdersJsonController {
 
-		@RequestMapping(value = "/search/sort", method = RequestMethod.POST, produces = "application/hal+json")
+		@RequestMapping(value = "/orders/search/sort", method = RequestMethod.POST, produces = "application/hal+json")
 		void someMethodWithArgs(Sort sort, Pageable pageable, DefaultedPageable defaultedPageable) {}
 	}
 }