Use a helper class to store parameters for dynamic mode

Use a helper classes to store parameter for dynamic mode instead of dict.

For example instead of this:

>>> params = simulation.dynamic   # It's a dictionary
>>> params
{'steps': ..., 't_step': ..., 'non_destructive_readout': ...}
>>> detector.set_dynamic(
       steps=simulation.dynamic["steps"],
       time_step=simulation.dynamic["t_step"],
       ndreadout=simulation.dynamic["non_destructive_readout"],
    )

we could have this:

>>> params = simulation.dynamic  # it's a dedicated class for these parameters
>>> params 
DynamicParameters(...)
>>> detector.set_dynamic(
       steps=params.steps,
       time_step=params.t_steps,
       ndreadout=params.non_destructive_readout,
    )