add expected epithelium calculation

[AxelRosendahlHuber]

Expected number of mutations using the dNdS mutation rate model as output. Main output: mutation_rates_all_depth.tsv giving the number of expected mutation rate according to the synonymous mutation rate

[FerriolCalvet]

@AxelRosendahlHuber sorry to bother you again, but could you please remove the index from the output table?
expected_mutratemutation_rates_all_depth.tsv

gene_name consequence mutrate cilow cihigh
1 ARID1A exp_syn 379 203.837295086813 705.437782508405
2 ARID1A exp_mis 1065.36914242731 571.237330709727 1989.51767205624
3 ARID1A exp_non 80.679612853698 44.1697639171942 147.428707027634
4 ARID1A exp_spl 114.354584152841 61.4476898233277 213.254505107473
5 CDKN1A exp_syn 53 28.5302192842399 98.5435879854078
6 CDKN1A exp_mis 143.164884988461 76.7734061192266 267.285241190367
7 CDKN1A exp_non 11.1031222219294 6.05264324073052 20.3830788563521
8 CDKN1A exp_spl 18.3753999495892 9.88621771155449 34.1874740779108
9 CREBBP exp_syn 353 190.061772932393 656.269287284128

also I am not sure whether you maybe wanted to add a / between expected_mutrate and mutation_rates_all_depth.tsv to make it inside the directory.

If you agree that these are two things that you would like to change, great, we can wait for this to be updated and then merge it directly, otherwise the execution still works, so I am happy to merge it this way as well.

Thanks