remove all import brightway2 or from brightway2 import statements

[ughstudios]

This change removes all import brightway2 or from brightway2 import statements

Checklist

• [ ] Keep pull requests small so they can be easily reviewed.
• [ ] Update the documentation, please follow the numpy style guide.
• [ ] Update tests.
• [ ] Categorize the PR by setting a good title and adding one of the labels: bug, feature, ui, change, documentation, breaking, ci as they show up in the changelog.
• [ ] Link this PR to related issues by using closing keywords.
• [ ] Add a milestone to the PR (and related issues, if any) for the intended release.
• [ ] Request a review from another developer.