We may want to remove the service manager if it turns out that it's enough to simply expect integrators to register beans through the BeanConfigurer introduced in and expect users/integrators to reference beans through configuration properties (like we do for the backend factory).

After all, globally scoped services make a lot less sense in Search 6, now that a single Hibernate Search instance can include multiple different backends and multiple different mappings, which could all be configured differently. The only globally scoped services that could make sense are those that are specific to the engine, and the engine doesn't do much...