Add decfile for exclusive Lb -> He3 pbar pbar decay

Decfile for simulating exclusive Lambda_b0 decays into helium-3 and two anti-protons. All daughters are required to be in acceptance (via DaughtersInLHCb).

The decfile is also required in Sim10 and was tested for Sim09 and Sim10, both.

Concerning the pipelines, there is the following warning:

• WARNING Track flag not compliant. Should be: 2. Please check.

  While helium-3 is not in the default list, it is a stable (charged) particle, which is why 3 is used for now.

added Sim09 Sim10 labels

requested review from @fabudine and @kreps

assigned to @rmoise and @hjage

requested review from @emmuhamm

approved this merge request

approved this merge request

merged

mentioned in commit b2a73d17

picked the changes into the branch cherry-pick-b2a73d17 with commit ecef2fa2

mentioned in commit ecef2fa2

mentioned in merge request !1899 (merged)

mentioned in merge request !1910 (merged)