ACTSFW-28 Introduce Particle Gun
Fixes ACTSFW-28. This merge request introduces a particle gun as a particle input option for fatras. Depends on !49 (merged) and should therefore be merged afterwards.
Edited by Julia Hrdinka
Fixes ACTSFW-28. This merge request introduces a particle gun as a particle input option for fatras. Depends on !49 (merged) and should therefore be merged afterwards.