Create new detailed guide categories for oil & gas

This migration creates eight new detailed guide categories for the Oil and Gas sector. A future change will use these categories to push the correct `industry_sector` tags into Panopticon for each detailed guide.

I've chosen to prefix each topic with quite a long slug for two reasons: to make it clear that these are different to regular topics; and, to avoid conflicts with the existing "Oil and gas licensing" category with the slug "oil-and-gas-licensing".