Bring documentation from python OpenTime library forward to the C++ methods and the docstrings

[ssteinbach]

The original python implementation of OpenTimelineIO had docstrings on many of the functions and methods in opentime. We should bring these forward into the C++ and also the python bindings so that users have that information readily available.

documentation:
https://github.com/PixarAnimationStudios/OpenTimelineIO/blob/last_pure_python/opentimelineio/opentime.py

[Viraj-Rana008]

I would like to contribute to this issue. Can you please share the link to the C++ methods?

[meshula]

The bindings, written in C++, are in src/py-opentimelineio.