scripts: add script to setup a development environment

Installs all required packages.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>
acpi: shutdown OSv on power button ACPI event

Signed-off-by: Gleb Natapov <gleb@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>