Completed module and tools that create industrial cells around input points

The industrial exposure of several European countries is defined in the European Seismic Risk Model 2020 (ESRM20, or SERA model) on a 30-arcsec grid. The ESRM20/SERA files only provide points (lon, lat) in which buildings exist, not the full definition of the 30-arcscec grid. We need to define the polygons of the cells of which the given points are centroids in order to then treat them as the equivalent of "districts" for the industrial case.

This merge request is the sixth of several that aim at implementing this feature. The following is included in this sixth merge request:

• Added the last three functions to GDE_TOOLS_create_industrial_cells.py:
  • export_modified_aggregated_model_file(): this function writes the DataFrame that contains the SERA exposure model modified to make reference to the cell IDs to a CSV file.
  • export_cells_to_geodatafile(): this function creates a geospatial data file of a given format, with the IDs and geometries of the generated cells.
  • which_countries_on_a_grid(): this function retrieves the list of countries for which the industrial exposure is defined on a 30-arcsec grid in the SERA exposure model. This information is provided in the EFEHR repository within an Excel spreadsheet called "European_Exposure_Model_Data_Assumptions.xlsx".
• Added the callable script SERA_creating_industrial_cells.py. This is the script that can be run to generate and export the industrial cells of a country or a list of countries. The output consists of a geodata file that contains the geometries of the cells, an updated version of the input SERA industrial exposure model, that includes the IDs of the generated cells, and a series of log files.
• Updated GDE_config_file_TEMPLATE.ini to include a section dedicated to SERA_creating_industrial_cells and the new parameter boundaries_type under the File Paths section.
• Updated GDE_TOOLS_read_config_file.py, the tools that read and process the parameters specified in the configuration file, to be able to process the new parameters.
• Expanded the documentation to cover this new feature:
  • Adjusted 02_Execution.md
  • Adjusted 04_Core_Scripts.md
  • Added 08_Industrial_Cells.md (and associated image files), fully dedicated to explaining the new feature

This feature is associated with dynamicexposure/collaboration#40

Previous merger request: !15 (merged)

Note: print statements are used to indicate errors/problems as a full logger functionality is not yet part of the prototype code (quite a manual logging system is set up in some core scripts, though; a full logger functionality will probably not be incorporated to the prototype code but go directly in the refactoring).

\approve @fd

\rfc @ds

\fyi @tara @shinde