Update the exisiting 'example_cell' folder to match the new state of the 'losscalculator

The already existing example_cell in the repository needs to be changed as below:

• 1. The folder name needs to be changed because the losscalculator as of now does not care if the assets are OBM or Cell and process the data regardless of this information. Thus this name is no more necessary.

• 2. Input exposure file needs to be preprocessed into an augmented exposure file that is as of now used as the correct input format for the processor.

• 3. The fragility functions should be introduced as a single XML file and not as a folder of CSV files(fragilities).

• 4. An intensity_measure_map.csv needs to be added that maps the ground-motion types introduced in the ground0motion field file and the fragility functions. (This parameter is optional and has a default value in the program, This means that it is only needed if the mapping between the name of ground motion types in gmf file and the fragility functions are different than in the default value)

• 5. The README.md needs to be updated.

• 6. Modify the run.sh.

• 7. Replace a new reference_results.

\rfc @cnievas @ds @shinde