Add support for token queries [APE-1244] #97
Description
Overview
Etherscan's API has a token index that we can use to speedup queries about different tokens
Specification
Once support for ApeWorX/ape-tokens#33 is added, detect if ape_tokens is available (check for ImportError) and import the relevant queries subclasses, then add support for them in the query engine if the classes are used