Provide an API to add interceptors to the default Spine services

[Vladyslav-Kuksiuk]

Currently, there is no way to attach ServerInterceptor's directly to the standard Spine services (e.g., QueryService, CommandService, SubscriptionService) during building the io.spine.server.Server.

Current Workaround

1. Build the io.spine.server.Server with bounded contexts.
2. Extract the configured Spine services.
3. Add Spine services to the io.grpc.Server wrapping the necessary ones with interceptors.