NGI_pipeline working version

It is still under testing but it should be pretty stable: @mario please review it carefully
Yeah like we discussed before, I think in this larger module we should just specify something like "DNA Variant Calling" and let that imply a certain set of steps which are implemented in the engine module (piper_ngi). So for instance here we'd just say "DNA Variant Calling" on the project level, and then piper_ngi would know that it needs to do QC, alignment, variant calling, possibly report generation, and so on.