REM: allow the possibility to specify acquisitions in type, 2D or 3D

[GiovanniGrieco]

Currently, we do not support the possibility of the following use cases:

• Allow the creation 2D and 3D REMs in the same simulation, this would reduce time required to build all of them.
• Simplify their declaration, maybe through a schema that introduces something like "type": "2D" | "3D"
• REM is only produced at the start of the simulation. It should be nice to trigger them in some way during the simulation.