Update sim.config_dict when saving a Simulation to a file

[fhagemann]

A Simulation is usually created from a config_dict, which is saved under sim.config_dict.
However, when properties of a Simulation are changed within the code, e.g.

sim.detector = SolidStateDetector(sim.detector, ADLChargeDriftModel())
sim.detector = SolidStateDetector(sim.detector, BoggsChargeTrappingModel())
sim.detector = SolidStateDetector(sim.detector, contact_id = 1, contact_potential = 4000u"V")
sim.detector = SolidStateDetector(sim.detector, ConstantImpurityDensity(-1e15))

this is not updated in the sim.config_dict.

This is, in general, not a big issue. However, when saving a Simulation to an LH5 file and reading it back in, the SolidStateDetector will be constructed from the sim.config_dict and will have forgotten about the settings set interactively.

How I envision this:
When saving, we could add a check which constructs a new Simulation from the current sim.config_dict.
It, then, compares all initial fields of the new Simulation (excluding e.g. electric_potential, electric_field, weighting_potentials, ... which may or may not have been calculated) to the existing ones. If there is a mismatch, it should update the sim.config_dict accordingly, before saving it to a file.

Up for discussion would be whether such a config_dict up-to-date test should be optional or not.
And if so, whether it should be on by default or not.