DisplacedSoftPion TrackPatternRecoInfo

Hi,

In preparation for the upcoming December LLP data-reprocessing, I'm adding functionality to uniquely identify tracks reconstructed with the DisplacedSoftPion configuration (previous these were merged with the LargeD0 TrackPatternRecoInfo).

Cheers, Matthew

Tagging RPVlL conveners: @kpachal ,@jmontejo