Add new ellipsoids, update ellipsoid tests

[Yozh2]

This PR adds many new ellipsoids for the Earth and other planets of the Solar system. It also adds tests for new ellipsoids.

The parameters are taken from Wikipedia and official documents (the documentation is supplemented with links to the source for each ellipsoid).

All pre-existing Earth ellipsoids (and their parameters) remain the same. I slightly adjusted the parameters of the Moon and Venus ellipsoids according to NASA Planetary Fact Sheet.