Added export functionality for user inputs in dashboard

[proy30]

Dashboard users can download a Python file containing their simulation inputs.

Verified accuracy by running trial test with FODO example simulation parameters, comparing results against the FODO example Python file.

Resolves #666.

[proy30]

UI - 9/29/24 (Download user inputs icon on top right side of toolbar)

input_simulation.py (what is downloaded to the user):

from impactx import ImpactX, distribution, elements

sim = ImpactX()

sim.particle_shape = 2
sim.space_charge = False
sim.csr = False
sim.slice_step_diagnostics = True

sim.init_grids()

# Initialize particle beam
kin_energy_MeV = 2000.0
bunch_charge_C = 1e-09
npart = 1000

# Reference particle
ref = sim.particle_container().ref_particle()
ref.set_charge_qe(-1.0).set_mass_MeV(0.510998950).set_kin_energy_MeV(kin_energy_MeV)

distr = distribution.Waterbag(
    lambdaX=3.998488477e-05,
    lambdaY=3.998488477e-05,
    lambdaT=0.001,
    lambdaPx=2.662353876e-05,
    lambdaPy=2.662353876e-05,
    lambdaPt=0.002,
    muxpx=-0.846574929020762,
    muypy=0.846574929020762,
    mutpt=0.0,
)
sim.add_particles(bunch_charge_C, distr, npart)

lattice_configuration = [
    elements.Drift(ds=0.25, dx=0, dy=0, rotation=0, nslice=25),
    elements.Quad(ds=1, k=1, dx=0, dy=0, rotation=0, nslice=25),
    elements.Drift(ds=0.5, dx=0, dy=0, rotation=0, nslice=25),
    elements.Quad(ds=1, k=-1, dx=0, dy=0, rotation=0, nslice=25),
    elements.Drift(ds=0.25, dx=0, dy=0, rotation=0, nslice=25)
]
sim.lattice.extend(lattice_configuration)

# Simulate
sim.evolve()

sim.finalize()

[ax3l]

Awesome, very nice!

Please don't forget to update the template one you add control for collective effects #690