Gen/GenCuts: Minor update for LoKi::GenCutTool & new LoKi::GenCutToolWithDecay, see LHCBGAUSS-1437
Port to 'Sim09-upgrade' the merge of branch 'LHCBGAUSS-1437.vanya-improve-generic-cut-tool'
See merge request !318 (merged) into 'Sim09'
(cherry picked from commit da2d0c1c)