[Dart8] support letters

Dear all,

please have a look at the attached letters and let me know if you find any issues.

Martina told me that the city of Vienna never supports conferences by cash, but instead, they invite the conferences to the historic city hall for an overwhelming welcome reception. I have never heard anything like that about Linz, but if we knew beforehand what they are willing to offer, it would be good to ask them for exactly this. Also, I don't have a good feeling whether 1000 Euros sounds very little or very much to them. I guess we just have to try.

Thanks, Manuel