Installing both C++ API and Python bindings

I am creating a Conan recipe for OTIO for the [aswf-docker project](https://github.com/AcademySoftwareFoundation/aswf-docker) and I want to build and install both the C++ and Python APIs. I believe this means configuring with:

```
-DOTIO_CXX_INSTALL=ON
-DOTIO_PYTHON_INSTALL=ON
```

At lines 55-112 of the top level CMakeLists.txt, if `OTIO_PYTHON_INSTALL` is set, `libopentime.so` and `libopentimelineio.so` end up getting installed somewhere like `/usr/local/lib/python3.13/site-packages/opentimelineio/`

This may be surprising for C++ clients which would expect to find `libopentime.so` and `libopentimelineio.so` in `/usr/local/lib/`.

I can see how when building a Python wheel, it would be advantageous to package both the C++ DSOs as well as the pybind11 wrapper DSOs in the same place, but for a non-wheels build, it seems it would be preferable to have the C++ DSOs end up in /usr/local/lib and have the pybind11 wrapper DSOs link against those, either relying on rpath or LD_LIBRARY_PATH.

Should there be (or is there) a mechanism which would differentiate a build for the purposes of creating a Python wheel from a non wheel build?

Start with the top-level CMakeLists.txt at lines 55-112 and configure a build with OTIO_CXX_INSTALL=ON and OTIO_PYTHON_INSTALL=ON. Compare the install locations of libopentime.so, libopentimelineio.so, and the Python wrapper DSOs for wheel and non-wheel builds. Done means the intended distinction and resulting install layout are agreed and verified.

Written by the indexing model from the issue text.