Scale increment and decimal fields according to cooked unit, so that the decimal and increments provided by meta data still work in the cooked display

 - Request list of all parameters, expecting device to lead each component with _HASH_CHECK cache value
 - Test for hash collision, if so our cache is valid and respond with _HASH_CHECK to stop listing
 - Else: let listing continue as normal to get updated param values
 - Store each cache by systemID + componentID

For #2586

Plumb through initial object mode on Vehicle

Allows parameter access from QML among other things

Used for unit testing