Add hydro dimension to ICs and warn/crash when wrong code version is used

Currently, it is perfectly possible to run a 1D or 2D problem with the 3D version of SWIFT. However, the results will be completely wrong. The dimension is written to the snapshot files, so it should be possible to also include it in the initial condition. The code could then warn or even crash if that number does not match the HYDRO_DIMENSION.