general: save the actually used ngs_tools script in results data folder
so far, we log the version of ngs_tools used in a project; however, referring to the ngs_tools version used is not always accurate as an individual project may exist of multiple analyses steps done over a longer period of time and which therefore depend on different ngs_tools versions; to ensure reproducibility it may be useful to copy the actually used script to the results output folder, i.e. featcounts_deseq_mf.R in the dge_analysis folders