Allow to configure custom SessionRepositoryFilter

[quaff]

Currently it's not possible to replace SessionRepositoryFilter with custom SessionRepositoryFilter like Spring Boot's ConditionalOnMissingBean, this PR introduce @EnableSpringHttpSession(sessionRepositoryFilterClass) like Spring Data JPA's @EnableJpaRepositories(repositoryFactoryBeanClass) to allow customizing SessionRepositoryFilter.

My use case is filtering requests conditionally, it requires extending SessionRepositoryFilter and overriding doFilterInternal(), but I found a workaround request.setAttribute(SessionRepositoryFilter.class.getName() + OncePerRequestFilter.ALREADY_FILTERED_SUFFIX, true) later, not sure we should add this feature, feel free to close it.