Generate `DiffEq(Tsit5())` simulation method to compare the results easily

[pvillacorta]

It would be nice if we could generate a new simulation method, DiffEq(Tsit5()), that uses get_spin_coords, get_grads, and get_rfs, so we can compare the results easily. I think it should be quite easy to make it work just for KA.CPU.

Originally posted by @cncastillo in #442 (comment)