[validation] more false positives for missing configuration validation

[martinlippert]

The validation to find missing @Configuration annotations on classes that contain @Bean methods needs to be improved. This is related to #1100.

The beans in "lite-mode" can be defined via @Bean methods basically on any Spring component, whether that is annotated with @Configuration or not, as long as the containing class is a Spring component. So we need to refine this validation to take this into account.

That means as soon as the class is annotated with @Component (or any sub-annotations of that), the validation should not be triggered.

In addition to that (checking for the annotation), the validation needs to take additional cases into account where a class turns into a Spring component without being annotated at all (e.g. the Feign case from #1100, Spring Data repositories, maybe more).