Adding utils for simple SES generation

[kurannn]

This PR introduces utils for simple SES generation. Below, you might see brief explanations of scripts.

ses_geo.py

• Provides a function for parsing geospatial data files (e.g., GeoJSON, Shapefile) and converting their geometries into OQ Engine polygon instances.

ses_source.py

• Provides a function to construct OQ Engine area source instance by combining MFD, PMF, and geometries.

ses_generator.py

• Provides a function to generate 1000 Stochastic Event Set (SES) by sampling earthquake ruptures from configured seismic sources using Monte Carlo sampling.