feat: add Prometheus telemetry collection with API-based time-window…

[Sypher845]

Description

This PR optimizes Prometheus telemetry collection by adding an optional API-based collection method with time-window filtering.

Key Changes:

• Added PrometheusExporter class that leverages existing KrknPrometheus for API-based metrics collection
• Updated get_prometheus_pod_data() with optional parameters: start_timestamp, end_timestamp, prometheus_url, prometheus_bearer_token
• Updated get_ocp_prometheus_data() to support new API collection method
• Implemented automatic fallback to filesystem backup if API collection fails
• Added time-window filtering with configurable buffers

New Configuration Keys (all optional):

• prometheus_backup_use_api: Enable/disable API collection (default: true)
• prometheus_time_window_minutes_before: Buffer before start time (default: 10)
• prometheus_time_window_minutes_after: Buffer after end time (default: 10)

Documentation

• Is documentation needed for this update?

Related Documentation PR (if applicable)

This PR helps in solving the issue #881 in krkn
Related Issue:* krkn-chaos/krkn#881

[github-actions]

Hi @Sypher845! 👋 One or more commits in this PR are missing a Signed-off-by line, which is required by our DCO policy.

Unsigned commits:

• 1576d70: Merge branch 'main' into optimize-prometheus-telemetry-collection
• 5f6f7ed: Merge branch 'main' into optimize-prometheus-telemetry-collection
• 0ac39f1: Merge branch 'main' into optimize-prometheus-telemetry-collection

To fix, rebase and sign off all commits:

git rebase HEAD~3 --signoff
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