Python 3.12 no longer supports calls to PyImport_AppendInittab
once initialized.
The call was redundant as Blender's `bpy_internal_modules` already
includes the "manta" module.
Resolve by disabling the call when Python's lifecycle isn't being
managed by manta-flow.
terminateMantaflow was never called, this leak is more of a technicality
since it's only called on exit.
Also make Py_Initialize/Py_Finalize optional in Pd:setup/finalize
as it caused Blender to crash, finalizing Python twice.
Add a patch to extern/mantaflow to keep track of changes in Blender
from up-stream.
Manta flow used the `__main__` namespace which it was executed in,
this caused a bug when calculating fluid from Python, which clears
it's `__main__` name-space after execution.
This caused Manta-flows name space to be cleared too.
Resolve this by creating a separate name-space for manta-flow.
Reviewed by: SonnyCampbell_Unity
Ref D15269
Includes preprocessed Mantaflow source files for both OpenMP and TBB (if OpenMP is not present, TBB files will be used instead).
These files come directly from the Mantaflow repository. Future updates to the core fluid solver will take place by updating the files.
Reviewed By: sergey, mont29
Maniphest Tasks: T59995
Differential Revision: https://developer.blender.org/D3850
