Add the option to dump polynomial system to files

[sumiya11]

Supported formats are:

• AbstractAlgebra.jl
• Bertini
• PHCpack

For example, to dump system in files in the current directory:

using ParameterEstimation
using ModelingToolkit, DifferentialEquations
solver = Tsit5()

@parameters a b
@variables t x1(t) x2(t) y1(t) y2(t)
D = Differential(t)
states = [x1, x2]
parameters = [a, b]

@named model = ODESystem([
                             D(x1) ~ -a * x2,
                             D(x2) ~ 1 / b * (x1),
                         ], t, states, parameters)
measured_quantities = [
    y1 ~ x1,
    y2 ~ x2,
]

ic = [1.0, 1.0]
p_true = [9.8, 1.3]
time_interval = [0.0, 2.0 * pi * sqrt(1.3 / 9.8)]
datasize = 20
data_sample = ParameterEstimation.sample_data(model, measured_quantities, time_interval,
                                              p_true, ic, datasize; solver = solver)
res = ParameterEstimation.estimate(model, measured_quantities, data_sample, dump_systems_to=".")