ESLint Config Migration: Export a function by default in modules

[filmaj]

Summary

This is a PR that should be merged into #1024 and incrementally addresses #842.

Impact

Before

✖ 773 problems (584 errors, 189 warnings)
  109 errors and 0 warnings potentially fixable with the `--fix` option.

After

✖ 771 problems (582 errors, 189 warnings)
  109 errors and 0 warnings potentially fixable with the `--fix` option.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.