Proper shared library handling for the C++ bindings

## Feature Request

Proposed Change to existing Behavior

## Description

1. right now libopentime.so and libopentimelineio.so are lacking an soversion. it would be nice to assign a proper soversion for those.
2. allow the python extensions to use the shared library.

## Context

This would make it easier to package OpenTimelineIO and use it with other programs olive.

No files, tests, or entry points are named. Start by tracing the build configuration for libopentime.so and libopentimeline.so and how the Python extensions link to them; done means the libraries have proper SONAMEs and the extensions use the shared libraries, with packaging for OpenTimelineIO and Olive considered.

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