Simple model of Illinois

[samgdotson]

This PR contains a jupyter notebook that builds a simple (woefully incomplete) model of Illinois. However, I think it provides a structure on which others can begin to contribute (@lshaver?).

What the model contains:

• Demand data for the ComEd zone of PJM and MISO Zone 4.
• Technology data maintained by PyPSA
• A single generator (open cycle gas turbine / OCGT)

What the model does NOT include:

• A transmission line connecting the two regions
• A complete set of generators
  • nuclear
  • coal
  • combined-cycle gas
  • onshore wind
  • offshore wind
  • utility scale solar
  • community solar
  • rooftop solar
  • storage options
• Technology data and costs from NREL
• Life-cycle carbon intensities for all technologies
• Time series data for the availability of solar and wind resources
• Existing generators (although the data are included in this PR, I did not add them to the model)
• Only models a single "year" (i.e., only one set of snapshots, there is no multi-year time horizon)
• Due to the above, there are no scheduled closures, either.
• Likely more things which are escaping my mind right now.

From this PR, we can also create a set of specific issues and tasks to cross off one-by-one (and facilitate sharing of tasks).

[lshaver]

Need to dive in a bit deeper but looks good for now.