Remove support for compiling imperative configurations

As of CHT 5.0, [declarative configuration is mandatory](https://github.com/medic/cht-core/issues/5906).
We should also remove support for compiling imperative configuration from cht-conf and banish [nools](https://github.com/search?q=repo%3Amedic%2Fcht-conf+nools&type=code). 