Consolidate scenarios / minimize code duplication for choice models

[sebhoerl]

A lot of the choice model code is duplicated across the scenarios. There are some options to go forward:

• Remove different city projects altogether and have one general eqasim RunSimulation that works on all scenarios (with custom parameters, settings, etc.)
• Keep the city projects but maybe move the general "does it all" choice model into a separate project

The reason is that I would, for instance, now like to use the ASTRA Zurich choice model for Paris, but it is not so easy, because there is a lot of implementational overhead. Whether to remove the city projects depends a bit pn how individual all the code around the choice model is (but I think there are not many individual components).