Move "Orbit" folder to be a child of the "Observatory" folder

[rzellem]

What do y'all think? @mrtommyb and @tddesjardins

[tddesjardins]

I'm either way about it. Moving it makes sense, but if anyone is opposed, I'm not bothered by its current placement.

[sepito]

It makes sense to me.

[rzellem]

@mrtommyb - what do you think?