Add some named Gauss-Jacobi typed quadrature rules

This merge request does the following:

• Add ChebyshevGaussQuadrature and GaussGegenbauerQuadrature, which are special cases of JacobiGaussQuadrature.

• LegendreGaussQuadrature is aliased as GaussLegendreQuadrature.

Those additions make my code using modepy to be a little bit more readable.