Add gamma distribution and other parameters to state_age_function

[lenaploetzke]

Feature description

Add gammasurvival and LogNormDistribution and parameters loc and scale to state_age_function These adaptions are necessary in order to be able to use the distributions from the supplementary material of the paper M. J. Kühn et al. „Assessment of effective mitigation and prediction of the spread of SARS-CoV-2 in Germany using demographic information and spatial resolution“ as parameters for the IDE model.

Additional context

Code can be copied from #771 Files:

• cpp/memilio/epidemiology/state_age_function.h
• cpp/tests/test_state_age_function.cpp

Checklist

• [X] Attached labels, especially loc:: or model:: labels.
• [X] Linked to project.