Added the best text editor (emacs, need you ask?) to the list of packages installed on all DTG servers.
Created stub entry for the upcoming DHCP server
There can only be one authorized keys file per user so don't add a second one wich never gets used as that just confuses

Signed-off-by: Daniel Thomas <drt24@cam.ac.uk>
Bump nexus version to 2.3.0-04

Signed-off-by: Daniel Thomas <drt24@cam.ac.uk>