Add source archiving to OpenSpending export (separate script)
Add source archiving to OpenSpending export (separate script)

This is a separate script because the export scripts is run on a
production server (or a server with access to the database) and we
don't want the production server to also do the archiving, we can
do that on some poor local machine.

johnjohndoe/spendb,openspending/spendb,CivicVision/datahub,pudo/spendb,openspending/spendb,CivicVision/datahub,pudo/spendb,pudo/spendb,spendb/spendb,CivicVision/datahub,openspending/spendb,johnjohndoe/spendb,spendb/spendb,johnjohndoe/spendb,spendb/spendb