refactor(utils): move util functions to utils.go

[zeek0x]

• move util functions to utils.go
• add tests
• improve test coverag
  • master: 98.6%
  • This PR: 98.7%

$ go test -cover ./... -coverprofile=cover.out && go tool cover -func=cover.out | grep total

Pull Request Checklist

Please ensure your pull request meets the following requirements:

• Open your pull request against the master branch.
• All tests pass in available continuous integration systems (e.g., GitHub Actions).
• Tests are added or modified as needed to cover code changes.
• If the pull request introduces a new feature, the feature is documented in the docs/doc.md.

Thank you for contributing!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.02%. Comparing base (3dc1cd6) to head (ab7e69e).
⚠️ Report is 224 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4467      +/-   ##
==========================================
- Coverage   99.21%   99.02%   -0.19%     
==========================================
  Files          42       44       +2     
  Lines        3182     2976     -206     
==========================================
- Hits         3157     2947     -210     
- Misses         17       20       +3     
- Partials        8        9       +1     

Flag	Coverage Δ
	?
--ldflags="-checklinkname=0" -tags sonic	99.01% <100.00%> (?)
-tags go_json	98.95% <100.00%> (?)
-tags nomsgpack	99.01% <100.00%> (?)
go-1.18	?
go-1.19	?
go-1.20	?
go-1.21	?
go-1.24	99.02% <100.00%> (?)
go-1.25	99.02% <100.00%> (?)
macos-latest	99.02% <100.00%> (-0.19%)	⬇️
ubuntu-latest	99.02% <100.00%> (-0.19%)	⬇️

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