Update signal-composer configuration for CES 2020 demo

The signal-composer configuration needs some updates to enable CES 2020 demo features:

• Signal definitions are needed to abstract the steering wheel CAN signals for applications

• Signal definitions are needed to abstract the CAN messages (vehicle and engine speed) currently being used by the dashboard application

• Additionally, it is possible that some configuration and an update to the low-can plugin may be required to drive sending a CAN message (or messages) to the cluster and/or external vehicle simulator for handling simulated cruise control state.