UC-150-1.1.4. Simulate calibration measurement - simulate flat fielding events

Add a simtool to simulate flatfielding events.

From Konrad's mail:

The flatfield simulations with ff-1m and ff-gct should be just right if the angular distribution of the light sources is chosen properly (user-defined data table). It requires proper measurements of that angular distribution by the instrument teams. In the ff-gct case, the angular and wavelength dependence on the reflection on the secondary mirror would be critical as well. That is another data table - which we use anyway.

What is generally too flat is the built-in flatfield events (LASER_EVENTS=1000 or such). Still OK for 1M but not realistic enough for 2M (even for direct illumination of the camera; no way to emulate ff-gct properly).

Requires a simple tool without queue submission:

• collect model parameters for flatfielding flasher/laser devices from camera teams
• retrieve telescope models from model databases
• run flat-fielding simulation with sim_telarray