U3 decomposition for matrices with determinant -1

[andrea-pasquale]

The following u3_decompositions function https://github.com/qiboteam/qibo/blob/19368f211c29d0831e5de2ed0b349cf51d235f12/src/qibo/transpiler/unitary_decompositions.py#L18-L35 holds only for matrices with determinant +1, however when executing on hardware we might want to execute gates, such as X, Y and Z with determinant -1. We need to find a way to generalize the previous formula to accommodate matrices with -1 determinant. I know that we already discussed about this but I decided to open the issue so that we don't forget.