Modernize xgen test

Use ThOr functors as much as possible in example. Add a description so users can use the example to test decay files. The goal is to advertise this at https://gitlab.cern.ch/lhcb-datapkg/Gen/DecFiles/blob/master/CONTRIBUTING.md .

More functors can be added as required by the simulation project. Please comment here.

Related to but not (yet) dependent on Analysis!846 (merged)

added DPA-WP3 Simulation testing labels

requested review from @dfazzini and @kreps

assigned to @pkoppenb

added 1 commit

• 8c8ec5e0 - Fixed formatting

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changed the description

changed the description

mentioned in merge request !645 (merged)

mentioned in merge request !646 (merged)

Note: Use Rec!2652 (merged)

added 7 commits

• 8c8ec5e0...62664d3f - 6 commits from branch master
• c9e119d8 - move to head

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approved this merge request

marked this merge request as draft

Changing to draft as I'd like to add Rec!2652 (merged) functors.

added 1 commit

• 4b99dd97 - Update option_davinci_tupling_from_xgen.py

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added WIP dependency label

removed WIP dependency label

added 11 commits

• 4b99dd97...2b7783ff - 10 commits from branch master
• 81e30c86 - Many option changes

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added lhcb-run3-cleanup label