Complete Python docstrings for wrapped SBProfile / C++ code

[barnabytprowe]

It seemed to me that the Python docstrings for the wrapped SBProfile objects could be added to, and given my recent documentation of the SBProfile class in C++ it seems I'd be a good person to take this on. This shouldn't break code, so I won't create a separate branch. I might ping @TallJimbo from time to time with a question / issue!

[rmjarvis]

I think we can close this issue. The relevant docstrings are all for our GSObject classes. Barney recently did a bunch of work making sure all the important wrapped classes have docstrings in python, and I don't think we need to do the same for the SB classes. Those should be considered implementation details for how the GSObjects work. So C++-only documentation probably makes sense.

[rmandelb]

I agree. This is 6 months old, so to put it in context, I'm not even sure we had an implementation for the base classes as containers for wrapped SBProfiles yet. Our C++ documentation for SBProfiles is good, our docstrings for the base classes is good. That's enough.