Feature: add/rename and document star generation speed to API

[L0laapk3]

It would be nice if the stars exposed their energy generation speeds:

star.energy_gen_flat = star.energy_capacity == 3000 ? 3 : 2;
star.energy_gen_caling = star.energy_capacity == 3000 ? .03f : .02f;

Update: while investigating for this Issue, I found a undocumented star.regeneration value. It would be nice to add this to add this to the docs, and to split it up instead of having to assume that scaling energy generation is just flat energy generation divided by 100.