Add extra field to service docs

[LindeSchoenmaker]

For contact information I would like to give two points of contact. Also to ensure a sustained point of contact. I can imagine this is the case for more people. For me it would help to give a current point of contact & also the contact information on the creator.

Current point of contact:

• Gerard van Westen (gerard@gjpvanwesten.nl)
  

Creator:

• Linde Schoenmaker (l.schoenmaker@lacdr.leidenuniv.nl)