Make the intel_adsp west runner starting to work on all the
intel_adsp boards. Changes include:
1. Make the cavstool.py work as a service in remote host
ADSP board and rename it to cavstool_server.py.
2. Active the runner and adds a common board.cmake file to
specify the default signing key for cavs boards.
Signed-off-by: Enjia Mai <enjia.mai@intel.com>
