soc/intel_adsp: Add twister integration script

This is based closely on the older cavsload.sh script, but updated to
keep up with interesting new twister behavior, with a cleaner
interface for CI integration that doesn't require editing the file,
somewhat better internal documentation, and with a more focused eye on
use as a twister tool specifically.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>