Generalize the function Cut::getCuts such that is works for multiple solvers without the need to edit the function (use templates)

[michieluithetbroek]

The function Cut::getCuts now returns a vector of CPLEX cuts. If one wants to use Gurobi, then one has to edit the function Cut::getCuts because 1) we need another return type, and 2) we have to call Cut::createGurobiConstraint instead of Cut::createIloRange.

We may avoid this by making Cut::getCuts a template function with two specialized template values (i.e., CPLEX and Gurobi). To avoid that the new template function breaks with the current code we can set the default value of the template to CPLEX.

The function will then be called as

auto const cuts = cut_ptr->getCuts<CPLEX>(model.d_env, model.d_x, x_val, true);