Add immunization waning parameters to the covid epi params

[roecla]

With #140 sid will require additional parameters for how immunity wanes for recovered and vaccinated individuals (see the test_params.csv last six rows for which are missing).

One paper that seems to include a lot of the parameters that we are needing is this preprint

One thing to keep in mind is the contagiousness_factors of Alpha and Delta. These have to be set such that we match the decline in protection that is described in the paper above.