add displaced dimuon produced in smog2 collisions

Adding a line called "Hlt1SMOG2DisplacedDimuon" to trigger on dark matter candidate produced in a SMOG2 with a dimuon decay within the VELO.

The line should start at dimuon threshold mass, with the candidate displaced but with its momentum direction compatible with a primary vertex in the SMOG2 cell. This should be be a free line in term of rate, as we see in the test with pAr+pp simulation

 |*"Selected by Hlt1SMOG2DisplacedDiMuonDecision"  |     29807 |          1 |(0.003354917 +- 0.003354860)% |

The conditions:

• A candidate with a PV in the smog region [-541mm,-341mm]
• The decay vertex `z` of the dimuon pair located at [-541mm;inf]      
• muon track with pt > 500MeV       
• FDCHI2 > 100       
• Max vertex chi2 of 25        
• Mom IP < 1 mm       
• Invariant mass starting at 500MeV
• Min pt of dimuon 500MeV
• chi2Corr < 1.3

Goes with Moore!3299 (merged)