Filter wheel integration (e.g. with a neutral density filter)

[GernotMaier]

At least the LST calibration device has neutral density filters. This should be implemented.

see e.g. https://www.epj-conferences.org/articles/epjconf/abs/2025/04/epjconf_ricap2024_12003/epjconf_ricap2024_12003.html

2 Filter wheels [5] with 6 positions each, 5 neutral OD filters each (OD from 1 to 4 each
set) to tailor the dynamics of the laser signal on the camera

[GernotMaier]

This should be straightforward to implement with an additional configuration parameter (not model parameter).

ff-1m allows for different intensities in a run:

Example 1: ... --events 100 --photons 1e6,2e6,3e6 ...
will have 100 events each for the three intensities.
Example 2: ... --events 100,50 --photons 1e6,2e6,3e6 ...
will have 100 events for the the 1e6 photons case and 50 for the
remaining cases.