Changes to Det/VeloDet, Velo/ VeloDAQ and Event/VeloEvent to make the VELO detector element thread safe

This removed all of the mutables from VeloDet (except for thread safe MsgService access). DeVeloSensor was being used to pass information about the decoding state between VeloDAQ and FastVelo. There is a new TES object Event/VeloEvent/xml/VeloDecodeStatus.xml which is used instead. This means this change needs to be correlated with the equivalent one in Rec (Rec!440 (merged)) as Tf/FastVelo also needs to update as the methods it used to use in DeVeloSensor::Tell1EventInfo.

Note I made up a new ClassID for VeloDecodeStatus, 4009

See also LHCBPS-1680

I know the arguments about the message service are still going on but the current implementation works, so can be used and updated when a solution is found.