chore: Add relabeling and metricRelabeling to Service Monitor in Karpenter Helm Chart

[waruwat-dev]

Fixes #N/A

Description
This merge request enhances the ServiceMonitor in the Karpenter Helm Chart by adding support for relabeling and metricRelabeling. This allows users to modify labels and filter metrics before they are scraped by Prometheus.

Motivation
In some cases, users need to adjust labels or refine metrics to align with their existing monitoring setup.
Prometheus provides relabel_configs and metric_relabel_configs to modify or filter metrics dynamically, but the Karpenter Helm Chart currently lacks the ability to configure these options.

Changes Introduced

• Adds support for configuring relabelings, metricRelabelings in the ServiceMonitor.

How was this change tested?

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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[engedaam]

@waruwat-dev Can you walk me through relabel_configs and metric_relabel_configs work with the Prometheus scraper and an example of how they would be used?

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Pull Request Test Coverage Report for Build 15151860817

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Details

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• Overall coverage remained the same at 66.844%

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Totals
Change from base Build 15125720112:	0.0%
Covered Lines:	6913
Relevant Lines:	10342

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💛 - Coveralls

[pjastrzabek]

Exactly what we need now.

We want to have karpenter metrics, but it's also exposing metrics we do not care about for instance:

karpenter_cloudprovider_instance_type_offering_price_estimate

which is basically AWS pricing inside metrics with almost 5000 data points for each scrape

We have many clusters, we don't need that metrics from each of them (data is the same) and in fact we want to drop it completely.

Second usecase is, by default karpenter metrics do have many labels (more than 30) which is more than some stacks (like mimir) allow for by default. Droping some labels is what we do for some other helm charts after carefull review, but typicall helm charts allow for that. Karpenter one does not.

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[jonathan-innis]

LGTM 🚀