Setup Routes for Every Single US Power Plant

[vkoves]

Maybe a route like /power-plants/:plant-slug?

This can be hidden for now and log out the relevant data, then Viktor will come through and do a styling pass.

Relates to #184.

[derekeder]

Steps to take here:

• update data/scripts/get_power_plants.py to generate a unique URL slug for each power plant. Looks like we can use state and plant_name and python-slugify
• update gatsby-node.js to generate pages for each unique slug. Here's an example of how to do that with a graphql query: https://gist.github.com/derekeder/1311af63c8db8e23992b5cebdb134973
• create a component template called /src/components/power-plant-detail.js similar to /src/components/state-detail.js
• set up the power-plant-detail.js to do a graphql query to grab the power plant details based on the slug value and print out the data in a console.log() statement
• hand it over to @vkoves to do the front-end design!