Accessibility of LFI DEMs from server

[jlandmann]

To run CRAMPON operationally on the server, we currently need VPN access to fetch all the LFI DEMs from speedy-11-12-fs.wsl.ch (speeds seems to be closed within the WSL domain).
ISG doesn't allow our servers to be within a VPN, so we need to think of a different solution.

Trying to access speedy without being in VPN leads to an ugly console crash without proper error message that @lgeibel has experienced.