Renames columns to outputs in driver & ResultMixin build_result function

[skrawcz]

The framework is generic, not only for tabular things. So removing
this language to not box people in.

Changes

• changes use of columns to outputs in result mixin build_result().
• changes use of columns to outputs in driver code.

Testing

1. Unit testing FTW.

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows the standards laid out in the TODO link to standards
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Testing checklist

Python

• python 3.6
• python 3.7

[elijahbenizzy]

Fix conflicts but it looks good