Python bindings for absl::Status cause ODR violation #20

The issue can manifest itself in multiple ways. One of the most straightforward examples is that returning an absl::Status with a payload from C++ to Python can cause the process to crash (approximately 1 in 50k times; code that reproduces the issue: https://github.com/apronchenkov/pybind11_absl_cord_odr_issue).

It appears that the root cause of the issue seems is that pybind11_abseil includes statically linked components of Abseil, which may conflict with Abseil usages within the Python extensions.