Validate registrations

[Keboo]

In many cases AutoDI knows what is being registered, and knows what dependencies may be asked of it.
It would be great if there was an opt-in warning for detecting when a dependent service may be used, but is not registered.
I would imagine the logic would be something like:

1. Iterate over all of the registered types and build a list of their dependencies
2. For each of the dependencies ensure that there is a matching registration
3. Display warnings for all dependencies that are not registered

Consider possibly checking the setup method as well, or at least allowing for a run-time method that can do the checks.

This would also require making this feature opt-in, as well as being able to ignore types.