Implement import tracking

I think false positives like those reported in #356 (and probably some false negatives as well) are prevalent across multiple lints and one way to solve them would be to use some form of import tracking.

I've come up with some examples below, but this is just a very rough draft.

from itertools import groupby

imported_modules = {
    "itertools": {
        "name": "itertools",
        "imports": {
            "groupby": "groupby"
        }
    }
}

from itertools import groupby as groupby_as

imported_modules = {
    "itertools": {
        "name": "itertools",
        "imports": {
            "groupby": "groupby_as"
        }
    }
}

import itertools

imported_modules = {
    "itertools": {
        "name": "itertools"
    }
}

import itertools as itertools_as

imported_modules = {
    "itertools": {
        "name": "itertools"
    }
}

Then in the lint to get the itertools id you'd use imported_modules["itertools"]["name"], and to get the groupby id you'd use imported_modules["itertools"]["imports"]["groupby"].

Is this something that we would be interested in adding?

Start by reviewing the false-positive and false-negative examples in this issue and the related report in #356. Determine which lints need import information and agree on the tracking representation and integration scope; done means the proposal is specific enough to implement and its behavior is covered by examples or tests.