Documentation of Python model life-cycle and Python library configuration

[zhwu95]

Is your feature request related to a problem? Please describe.

When I'm integrating simics into SST as a separate thread alongside the main component thread, I encountered a deadlock where simics is trying to acquire the Python GIL.
After digging into it a bit more, I found that it is likely due to Py_Finalize() not being called by default, and the calling of it must be enabled through the setCallPythonFinalize module method (here).

I understand that you are experimenting some features and hence it is not called by default, but I believe that this behavior should be documented lest someone spends their time on this later on.

Describe the solution you'd like
Some explanations/clarifications about the use of python models and their life cycle in the sst-core document would be quite helpful.

Describe alternatives you've considered
N/A

Additional context
N/A