Change desktop icons to point to new symlink scripts
Rework VirtualBox script

To fit with previous changes of symlinking Karoshi scripts into /usr/bin,
the VirtualBox script has been reworked to run at login and create the
necessary folders there. Launching VirtualBox now directly launches it,
while a new script 'karoshi-virtualbox-mkdir' has been created. This also
means that NOPASSWD sudo privilages are only given to the helper script.
Remove silly log logic
Move virtualbox-mkdir code to PAM

Having PAM do the work setting up a directory for the user reduces the
privilages required for the user. Logging can also be done more effectively.