Fixed download link for DFT-D3
Partial fix for #1145 (closed) (broken link for DFT-D3); the Niflheim Fjorm part may have to wait as it seems to be some Open MPI issue on the login node
Partial fix for #1145 (closed) (broken link for DFT-D3); the Niflheim Fjorm part may have to wait as it seems to be some Open MPI issue on the login node