There are still lots of instances of the constant EARTH_RADIUS in the code base.

This is especially bad for code which is supposed to work for other planets.

One of the crucial places are the (Azimuthal)Projection classes. We need to introduce the actual planet radius there.

Please create a set of patches for two approaches:

- expose a planetRadius property inside the ViewportParams class

- create a setPlanetRadius() method inside the AbstractProjection class

Create two separate patches for both approaches. The resulting patch should be fully functional. Display the orbits of Mars orbiters before and after applying both patches.

- provide a set of unit tests if possible.