[CI] run nilaway through golangci-lint as a custom module

[AshleyDumaine]

What this PR does / why we need it: Doing this, we'll be able to use //nolint:nilaway to disable false positives if they come up in the future since this isn't supported when running nilaway in standalone mode.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• adds or updates e2e tests

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.34%. Comparing base (dfdc4a5) to head (ab97eab).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #928   +/-   ##
=======================================
  Coverage   66.34%   66.34%           
=======================================
  Files          71       71           
  Lines        7961     7961           
=======================================
  Hits         5282     5282           
  Misses       2378     2378           
  Partials      301      301           

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