Job can be started without selecting fitness method

It is possible to start an IMP run without specifing a fitness methond in the `relation`. After the `input.py` is processed, the user gets presented with some properties of the IMP run, for example the simulation setups, software versions and optimiser properties, but there is no information given about the chosen fitness methods for the different relations and their importance/weight.

This should be added and also some clearer messages could be designed to make the user aware that no fitness method or simulation software is selected.