Add "forbid" option for import/no-internal-modules

[guillaumewuip]

I would like to use import/no-internal-modules to allow all imports except some rules.

For example, given

import React from 'react';
import { Toolbar } from 'reakit/Toolbar';

import { thing } from '../dir2/subdir';
import { somethingElse } from '../dir2/subdir/file';

I would like to allow everything except reakit/Toolbar and dir2/subdir/*.
Because this should work for the full codebase (lot of node_modules dependencies, complex directory tree), I prefer maintaining an exclusion list of what is forbidden than an inclusion list of what is allowed.

Would you accept a PR to add a forbid option to import/no-internal-modules to be used like below ?

{
  ...
  "rules": {
    "import/no-internal-modules": [ "error", {
      "forbid": [ "reakit/Toolbar", "*/dir2/subdir/*" ]
    } ]
  }
}

[ljharb]

As long as forbid and allow are mutually exclusive, that seems like a reasonable semver-minor PR.