Update nexus version to current
Initial work on a ssh maven mirror to allow external users to connect to our maven repository over ssh
Use an upstart job to ensure that sshmirror is actually mounted ro

By default it doesn't work as a remount is required for the ro to take effect
Include updated monkeysphere module with sshd_config.d folder support
Use sshd_config.d to make appending to sshd_config possible for maven sshmirror
Put the mirror mount in a subdir of the chroot

Otherwise ssh will complain as the chroot dir is not root owned
Add monkeysphere keyids for maven mirror