Implement Godunov solver with the experimental Euler system class
In order to limit the amount of loops in the code, the file HydroEulerSystem.hpp is planned to be replaced by HydroEulerSystemExpermimental.hpp where the data is stored as elements of the class state (e.g. u.p, u.p) instead of elements of an array (e.g. u[iP], u[iP]).
In this branch, we want to write the Godunov Solver that deals with this new "System" class, it should be a fairly easy task as that has already been done for the all regime solver in:
experimental/AllRegimeAcousticKernelExperimental.(c/h)pp. experimental/AllRegimeTransportKernelExperimental.(c/h)pp.