should be able to query config variables without registering a handler

In order to figure out what config variable is saved to, you need to have a handler registered, which gets called at config load time.
Expectation is that the user will keep this value around.

We should remove this requirement, so that you can load values on demand. This becomes useful for cases the amount of stored data is large (e.g. bluetooth LTK), and where it's used only for a short period of time.