Refine inner beans arrangement

[mp911de]

When defining repository factory beans, we make use of inner beans to e.g. load named queries. Ideally, we register a single bean that gets reused across multiple factory beans.

[mp911de]

RepositoryBeanDefinitionBuilder heavily uses inner beans for named queries (PropertiesFactoryBean, PropertiesBasedNamedQueries). It would make sense to revisit and simplify this arrangement.