Python packaging and binding

[icui]

Add configuration for scikit-build and expose select functions via pybind11. Python code will be maintained in a separate repo specfempp-py (PyPI).

• Remind users to create a new python environment before installing (there may be linking issues when sharing the same environment with obspy).
• Build specfem with pip install (via scikit-build-core) #173
• Hello world for pybind
• Call main specfem workflow with Python
• Define runtime configurations with Python
• Determine if we need to specify build-dir in pyproject.toml
• add binary to pip path #177
• add shared library to pip path