feat: Add build_info metric with version, sha, goversion labels

[nantiferov]

Fixes kubernetes-sigs/karpenter#665

Description

As described in the issue, it's useful to have metric with at least version label, which makes easier to find what version was running at each time to correlate issues related to update, etc. Example https://www.robustperception.io/exposing-the-software-version-to-prometheus/

So far this implementation might be a little bit "naive", since I tried to adopt existing code in project to add one more metric. If this should be done in a different way, I'm glad to have a feedback.

Also, I added only version and golang_version labels, because they're already available. In theory more can be added, like branch or sha. Not sure if they're very useful though.

I checked contribution guide and tried to follow it.

How was this change tested?

Did make apply with pushing image to temporary ECR registry and deploying karpenter to my test EKS cluster.
All works fine, example of metric output:

# HELP karpenter_build_info A metric with a constant '1' value labeled by version from which karpenter was built.
# TYPE karpenter_build_info gauge
karpenter_build_info{golang_version="go1.21.4",sha="e19bcd7-dirty",version="e19bcd70"} 1

Does this change impact docs?

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

Not sure, probably need to update docs, but closer to PR be ready to merge.

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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[nantiferov]

I think PR is ready for review, please check it.

Also, let me know if docs should be updated. Quick check shows that I can open PR to update metrics page https://github.com/aws/karpenter-provider-aws/blob/main/website/content/en/docs/reference/metrics.md

[coveralls]

Pull Request Test Coverage Report for Build 7132706642

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A quick fix for this PR: rebase it; your next report should be accurate.

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 82.495%

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Totals
Change from base Build 7110677239:	0.006%
Covered Lines:	4920
Relevant Lines:	5964

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💛 - Coveralls

[jonathan-innis]

LGTM 🚀