Add download from plougshare

[scarlehoff]

The pinecard in this case needs to be just an url to plougshare:

e.g., https://ploughshare.web.cern.ch/ploughshare/db/pinejet/pinejet-atlas-wm-arxiv-1109.5141/pinejet-atlas-wm-arxiv-1109.5141.tgz

with a metadata.txt and possibly a postrun.sh if there is something that needs to be modified to make it compatible with our data (e.g., fb -> pb or whatever)

[felixhekhorn]

maybe this is not a strict duplicate, but very close to #3

[scarlehoff]

Both things are necessary since we have the old grids, although #3 is actually quite well covered by @Radonirinaunimi's docs https://pinefarm.readthedocs.io/en/latest/run.html#converting-pre-existing-interpolation-tables