Add new function compute_potential in PoissonFFT.
Complete PoissonFFT to a working mode. Pre-prepare for benchmarking.
Implement n_macroparticles, n_particles, charge conventions in bunch.
Merge with master after merge from HBartosik.
Refactor for n_particles, id; introduce new bunch methods set_bunch_physics and set_bunch_numerics.
add longitudinal track method when reading from wake table, take beam loading theorem into account for longitudinal wakes from wake table (lonigutindal wake in front is neglected)
Finish refactoring and add methods set_bunch_xxx instead of set_scalar_quantities.
final adjustments after the merge with Kevin's branch, change input from GeV to eV for energy, change mass definition in input from 1 for protons to e