tools: Add configuration generator

Adding a helper script to generate a configuration for the root cell.
The script can also generate another script to collect all the necessary
files on a remote machine.
Both scripts can be accessed through the jailhouse command.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>