[NGINX] Add nginx-extras for additional modules
Remove DEBIAN_FRONTEND exports

Only surpresses some warnings, but doesn't do anything else.
[Baikal] WIP
[WIP][OwnCloud] Update OwnCloud to use a Ubuntu 14.04 image
[WIP][OwnCloud] Delete autconfig.tpl.php after generating config
[WIP][OwnCloud] Set correct user for nginx, and increase worker processes to 4