Extract `update-vm.sh` and packaging scripts into a separate Repo

[tknerr]

We duplicate the `update-vm.sh´ script for each developer VM, and improvements don't flow back into a single source of truth.

Since it's generic for all developer VMs it should stay in it's own repo (which describes our developer VM approach, hosts the update-vm .sh and .bat scripts, and also the script for packaging / exporting vm images)