Illustrate importing EI with ecoinvent_interface

[tngTUDOR]

Current

There is a section of the book for bw25 where we show how to import EI db using the ecospold single output importer, directly from ecoinvent downloaded files.

Expected

Illustrate also how to import ecoinvent using the ecoinvent_interface package.

[tngTUDOR]

🤭 I have gist that gives already some working code:

import ecoinvent in 2 lines

[michaelweinold]

Adding @alyabolowich and @KarinTreyer to this conversation 😇