More sensible names and raise deprecation warnings

* Change the settings variable for backends to name it after this component.
* Rename the backend for the same purpose.
* Throw warnings for the imports in `utils.py` that have been marked deprecated for almost two years.

These will go into the 1.3 release. The goal is to remove these legacy items in the next 1.4 release (which is TBD and probably in the far future; I still want the model_provided backend to go into 1.3.)