DESTATIS: use english labels
Some DESTATIS time series names mix german and english terms,
e.g "Deutschland - Zölle - Revenue from taxes
" (DG.VGR-STE-22.STEU01).
English translation of german terms is normally available in SDMX files.
Series above should be named "Germany - Import duties - Revenue from taxes
"
Fix convert script to use english translation when available.