PEP-0684 adds support for a Per-Interpreter GIL in Python 3.12.

In order to support this feature, we will need to implement Multi-phase extension module initialization in our extension modules which was done in PYTHON-3745.

To test this we may need to wait for a Python API to be implemented (PEP-0734 Multiple Interpreters in the Stdlib).

We also need to add the Py_MOD_PER_INTERPRETER_GIL_SUPPORTED flag to our C extensions.