misc (event-display): Add jet origin

[matiasmantinan]

Add origin for displaced jets. User's guide was updated as well. This pull request arose from question Displaced jets #691. As an example, here is an events.json with three jets:

{ "1": { "Jets": { "three_displaced_jets": [ { "origin_Z" : -1000, "origin_Y" : 1000, "origin_X" : -1000, "pos": [ [ -0.4987947940826416, -0.49609166383743286, -80.730889320373535 ], [ 0.5028243660926819, -0.8267080187797546, -80.741073608398438 ] ], "eta": -0.8143964409828186, "phi": -2.9927451610565186, "energy": 326618.375 }, { "eta": -0.40384864807128906, "phi": 0.24317990243434906, "energy": 245776.171875 }, { "origin_Z" : 1000, "eta": 2.8462071418762207, "phi": 2.033921003341675, "energy": 135842.859375 } ] } } }

The resulting event looks like this:

[EdwardMoyse]

Apologies for the delay, but thank you for this improvement!