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.

[fhagemann]

Could be something like this (I've written a test case that would be broken now):

using SolidStateDetectors
using Unitful
using Test
T = Float32

@testset "Config dicts" begin
    
    # read in an example configuration file
    sim = Simulation{T}(SSD_examples[:InvertedCoax])
    
    # check the correctness of the configuration dict
    @test sim == Simulation{T}(sim.config_dict)
    
    # it is not the same when something is overwritten
    sim.detector = SolidStateDetector(sim.detector, contact_potential = 10000u"V", contact_id = 1)
    @test sim != Simulation{T}(sim.config_dict)
    
    # however, one can update the config dict to everything that was changed
    @test_throws UndefVarError update_config_dict!(sim)
    @test_broken sim == Simulation{T}(sim.config_dict)
    
end

where in the end, a function update_config_dict! would iterate through the fields in the config dict and update it accordingly.