new slogin-otpw server - generate a new pad

mgk25 has just released version 1.5 of OTPW which does not need to use $HOME for the pad. This allows per-host local pads, removing the problems on NFS sec=krb5 systems. The DNS name slogin-otpw now points at the testing slogin server. Any users need to generate a new pad by logging in and running cl-otpw-gen.