onnxruntime

Re-work global objects dependancies in pybind layer. (#14941)

### Description
Re-work handling of static objects in pybind.
Make sure we ref-count Environment from Sessions.

The following has been done:

- Make global objects function static. This ensures that the objects are
constructed on demand. The first object constructed is destructed last.
This is platform independent.
- Make global objects ownership shared as suggested by pybind since they
are not surfaced at Python level, and they cannot be referred to by
dependent python objects. Verified that all python objects are GCed
before globals are destroyed. This takes care of inference session
dependency on environment and its default logger and this is also
platform independent.
- Utilize pybind atexit mechanism to clear execution providers and
unload CUDA libraries (as suggested by
https://github.com/microsoft/onnxruntime/pull/14903) . Since this is
registered for module exit, it takes place before any other global are
destroyed and clears shared objects state or even unloads the libraries.
This should also work in a platform independent way.

### Motivation and Context

- Global object destruction order is managed manually and that becomes
source of trouble. We want to make it deterministic and platform
independent.
- Frequent hangs in Python layer due to the static object's destruction
order. Some of the Python session objects are being garbage collected
after main exits and they require ORT environment to be alive. (Use
after free)