make otel metric options more configurable

[havetisyan]

Description

To provide more control over the generated metrics and reduce cardinality issue

Contribution Checklist:

• The pull request does not introduce any breaking changes
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

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[gemini-code-assist]

Summary of Changes

Hello @havetisyan, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the OpenTelemetry metric integration within Athenz by providing more detailed control over metric cardinality. It introduces distinct configuration options for handling domain-specific attributes in histogram and counter metrics, allowing for independent management of how request and principal domain names contribute to metric labels. Additionally, new properties enable the optional skipping of these domain-specific metrics, offering greater flexibility in optimizing metric data volume and cost.

Highlights

• Granular Metric Configuration: Introduced separate configuration properties for managing domain-specific attributes for OpenTelemetry histogram and counter metrics independently.
• Cardinality Control: Added new properties to optionally skip the recording of request and principal domain metrics, further reducing metric cardinality when domain separation is enabled.
• Code Refactoring: Updated the OpenTelemetryMetric class and its factory to incorporate the new configuration options, ensuring proper application of these settings to metric recording logic.
• Enhanced Test Coverage: New test cases were added to validate the behavior of the newly introduced skip domain metric functionalities for both histograms and counters.

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[gemini-code-assist]

Code Review

This pull request enhances the configurability of OpenTelemetry metrics by separating the settings for histogram and counter metrics, and adding options to skip domain-specific metrics to control cardinality. The changes are logical and well-implemented, with corresponding updates to tests.

A key point to consider is that renaming the configuration property athenz.otel_separate_domain_metrics to athenz.otel_separate_domain_histogram_metrics constitutes a breaking change for users who might have the old property configured. It would be beneficial to update the pull request description to acknowledge this.

I have provided a few suggestions to fix minor typos, improve test clarity, and enhance maintainability.