'Signature' to be available as a string variable

Currently the Signature of a configuration, which is unique every time the Save button is pressed is NOT available as a string variable in the Programming Tab of PowerVision.

We need that available as a read-only string variable so that we can track the Original murphyConfigs whenever sharing with OEMs making their own modifications on the murphyConfig files we provide. Either by having that Signature variable show up on one of the Menu screens OR by broadcasting that on CAN so that CANlog files taken from the field can tell us the identity of the root murphyConfig file.