Implement improvements identified by static linting

[liamfallon]

• Use "_" instead of names for unused function parameters
• Use "_" instead of names for unused variables
• Remove unused functions and variables
• Replace fmt.Errorf with errors.New when error message contains no formatting

[nagygergo]

Should the static checker be part of the pull_request github action?

[liamfallon]

Should the static checker be part of the pull_request github action?

The static check is performed by VSCode in the background as one is coding. This static checker exists for go, it seems like a good idea to trigger this in a github action. I have added it to the agenda for discussion at the next SIG-3 meeting.

[efiacor]

/approve
/lgtm

[nephio-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: efiacor, liamfallon

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[liamfallon]

/retest