Picard Duplicate Fraction is wrongly named "Percentage"

The result table of collected results contains a column named `Picard_mqc-generalstats-picard-PERCENT_DUPLICATION`, when actually this is a proportion, not a percentage. The naming bug happens [here](https://github.com/MPI-EVA-Archaeogenetics/helper_scripts/blob/49ef31f4b481f25a5b58ec2ee1a99d2959992992/Autorun_multiqc_stats_collect/collect_results.py#L311)

