Big refactor v0.30

All test pass, except for the TestConfig suite, which is not too critical as the
plan for this version onwards is to avoid configuration as much as possible.

examples/events_and_messages/cars_sim.py

@@ -232,12 +232,10 @@ class Passenger(Evented, FSM):
         self.die()
 
 
-simulation = Simulation(
-    name="RideHailing",
-    model_class=City,
-    model_params={"n_passengers": 2},
-    seed="carsSeed",
-)
+simulation = Simulation(name="RideHailing",
+                        model=City,
+                        seed="carsSeed",
+                        model_params=dict(n_passengers=2))
 
 if __name__ == "__main__":
     simulation.run()