Improve the granularity of detection within go.sum/go.mod

[pombredanne]

Description

It would be great to improve the granularity of detection within go.sum/go.mod especially since:

1. both files may contains redundant dependencies
2. from and origin and license perspective the is too much details with all the imported subdirectories
3. there are typically test tools or test-only imports that are present in go.sum/go.mod but never used in a built production binary