Replace `artis` table name with `trade`

[theamarks]

ARTIS is the model, trade and consumption tables are the datasets produced from the ARTIS model. Trying to clarify and standardize how we talk about the datasets. ARTIS and trade were once synonymous, but now the consumption table is as useful if not more useful, we need to distinguish for users and our selves moving forward.

• rename mini_artis --> mini_trade
• update all functions, examples, and README figure generation scripts to use renamed mini_trade