More detailed parameterised scattering for no UT scenario
Introduce reference EndUT node in PrKalmanFilter. This way the scattering transition is split into two in the case of no UT scenario.
(also renames TT->UT in few places)
Aims to address #379 (closed) and observed mass peak shifts.
Needs LHCb!3969 (merged) Allen!1160 (merged)
Closes #379 (closed)
Edited by Andrii Usachov