Map EPSG codes of UTM on ED50 datum

As we did with WGS84 and SIRGAS2000 here: https://github.com/JuliaEarth/CoordRefSystems.jl/blob/6f63cc581b3ca9da06b49b7900cf6a7199ecfcd8/src/get.jl#L141-L160 One example of EPSG code to be mapped: https://epsg.org/crs_23031/ED50-UTM-zone-31N.html