Install unattended-upgrades

I think it is a good idea to install unattended-upgrades when setting up the system.

I've bumped into the following issue, running installer on an outdated Ubuntu

"[ERROR] The running kernel version (5.4.0-56) does not match your installed kernel modules (5.4.0.62.65). Currently there is no quota available! Please reboot your server to load the new kernel and run the autoinstaller again or start it with --no-quota to disable quota completely. (/lib/os/class.ISPConfigDebianOS.inc.php:946)" 

I think this is unrelated. The error message tells you what to do, and installing unattend-upgrades would not fix this.

I would prefer the setup to raise a warning for me: If apt-update detects a new version of kernel, installer should update the kernel and abort installation, with reboot recommendation. This could be subject to a separate issue. 

Setup with argument --use-unattended-upgrades

I'd rather use --no-unattended-upgrades and install it by default :)

mentioned in merge request !3 (merged)

added Feature Request label

assigned to @thom

closed with merge request !3 (merged)

mentioned in commit e157feb1

added Implemented label

mentioned in issue #37