Add an optional output file with a summary of un-sited/sited power plants

[kmongird]

Add a yml or similar output file that contains information on the number of sited plants and number of plants that were unable to be sited in a region by technology.

A suggested yaml structure could be the following for each technology, one output file per run:

cerf_biomass_igcc_ccs_recirculating:
    sited_plants: 20
    unsited_plants: 2

If it's an optional file output, it will also need to be added as a new component in the configuration file. One suggested option is to specify new settings in the following way by adding the last two components:

settings:
  run_year: 2025
  output_directory: 
  randomize: true
  seed_value: 0
  region_raster_file: 
  region_abbrev_to_name_file: 
  region_name_to_id_file:
  output_siting_summary_file: true
  siting_summary_output_directory: