Clean and make public the Full ICSolver for rescaled energy density and momenta as inputs.

[JCAurre]

The current Full ICSolver solves the Hamiltonian and Momentum constraints for a real scalar field using the CTT formalism. Right now, the inputs are the scalar field profile \phi and the momenta \pi. The solver computes the corresponding energy density \rho and momentum densities S_i.

However, due to the properties of the differential equation, one needs to rescale these quantities to ensure the uniqueness of the solution. This implies the user loses control of the initial data of the fundamental fields \phi and \phi when rescaling back.

Our goal now is to modify the code so that we don't input fundamental fields but directly the rescaled energy density \bar{\rho} and the rescaled momentum densities \bar{S_i}.