🚀 [Feature]: Update otelfiber to use actual OpenTelemetry semantic conventions

[RyabovNick]

Feature Description

The current implementation of the otelfiber package uses outdated OpenTelemetry semantic conventions. Several naming conventions have changed, and the most critical update is related to the http.server.request.duration metric. The unit has changed from milliseconds (ms) to seconds (s).

A list of deprecated attributes/metrics can be found here:

Metric: http.server.request.duration

HTTP Deprecated Attributes

Network Deprecated Attributes

Additional Context (optional)

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Code Snippet (optional)

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Checklist:

• I agree to follow Fiber's Code of Conduct.
• I have checked for existing issues that describe my suggestion prior to opening this one.
• I understand that improperly formatted feature requests may be closed without explanation.