Add /rdw/ redirection

Added redirects for:
- `/rdw/` to http://www.rdw.nl/
- `/rdw/vehicles` to RDW Vehicles vocabulary in JSON-LD (currently a gist) https://gist.githubusercontent.com/jaw111/9729470/raw/1f883da00be27fbdefb2d4892555f47761a8e786/gistfile1.json