Add timeutil package

[AntonioMA]

Description

Implements an alias for time.Duration that automatically marshals/unmarshals to JSON in human readable form.

Checklist:

• The make x command has been run successfully without any error or warning.
• Any new code line is covered by unit tests and the coverage has not dropped.
• Any new code follows the style guidelines of this project.
• The code changes have been self-reviewed.
• Corresponding changes to the documentation have been made.
• The version has been updated in the VERSION and examples/service/go.mod files.

Type of change:

• Bug fix (non-breaking change which fixes an issue) → The patch number in the VERSION file has been increased.
• New feature (non-breaking change which adds functionality) → The minor number in the VERSION file has been increased.
• Breaking change (fix or feature that would cause existing functionality to not work as expected) → This requires a major version release.
• Automation.
• Documentation.
• Example.
• Testing.

[coveralls]

Pull Request Test Coverage Report for Build 5728231507

• 26 of 26 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 5725379768:	0.0%
Covered Lines:	4984
Relevant Lines:	4984

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💛 - Coveralls

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

100.0% Coverage
0.0% Duplication