DARES - demandeurs d'emploi données nationales - données brutes

As system, I need to obtain data from Excel file ser_nat_brut-lala39bim59_.xls in order to store DARES data

Criteria of acceptation: visual inspection of data and metadata

Treat only sheets similar to the ones in CVS Excel file ser_nat_cvs-lala39bim59_.xls, following similar methodology t o issues #64 (closed) #65 (closed) #66 (closed) #67 (closed) #68 (closed) #76 (closed) #77 (closed) #78 (closed)