Making `ExportMap` available in `eslint-module-utils`?

[adamhamlin]

The ExportMap generally makes possible lint rules which evaluate metadata in files/nodes imported by the "current" file. For example, the import/no-deprecated rule uses it to check for @deprecated doc tags for any imported items.

This is a powerful utility, and could be used to condition other custom rules--e.g., perhaps by looking at different doc tags, or looking at other node metadata entirely.

Would you be open to a PR that exposes ExportMap/ExportMapBuilder in the eslint-module-utils package like is done for the moduleVisitor utility?

Thanks!