Add support for @Spy annotation

[anuragagarwal561994]

Feature description

Mockito provides a @Spy annotation, sometimes one needs to verify if on the injected instance of the bean if a specific method is being called.

For example, if I have setup a @PreDestroy hook and I want to verify in my test case that it is working and my instance is a concrete instance, I can't verify if the method was called unless I use @Spy on it.

In test environment we should add a BeanCreatedEventListener to add spy over all the beans created which were annotated with @Spy or some similar control would be helpful.

[dstepanov]

PRs are welcome