Read adapter (or base quality-dependent) pre-trimming #80

@BenjaminWehnert1008 this has been on our list for some time: especially for amplicon data with constant 5' and 3' flanks around the mutated ORF – but also for read pairs with significant QC drop at the ends – it makes sense to ask users to specify these sequences for a consistent read pre-trimming.

There are different nf-core modules we could implement upstream, arguably trimgalore is the best choice since it connects directly from the FastQC outputs: https://nf-co.re/modules/trimgalore/