Initializing in `ServiceLocator` is a little trickier than I thought, since we'd need to teach the SL solution about the BootstrapLocator, and `Directory.GetFiles` is not our friend. I guess we could `#ifdef` out and always return empty in that case.

I'm torn, but in favour of doing the simpler thing now. If/when we expand the bootstrapper, we can relocate or add caching then, no?