Add Fresnel integral

[ErikQQY]

Hello guys, I notice there are Fresnel integral related docs there, but I don't see any implementation about Fresnel integral or auxiliary Fresnel integral, so I think this part is missing?

In MATLAB, we can use fresnels and fresnelc to compute the Fresnel integral, so I think it would be great to have that support in SpecialFunctions.jl

Besides, I notice there is an implementation out there: https://github.com/kiranshila/FresnelIntegrals.jl

[curio-sitas]

I ported the code of the repository you proposed in the package (see PR #407)
This is my first github contribution, please tell me if all is ok.