[WIP] Update observability OSS module

[aonz]

What this PR does / why we need it:

• [x] Add new OSS module and Terraform code to provision AMP (Prometheus), Loki, Tempo and Grafana.
• [x] Update ADOT to send metrics, logs and traces.
• [x] Inject OTel environment variables to the app deployments.
• [x] Migrate Kubecost module into OSS module and update to AMP.
• [x] Add website docs for OSS module.
• [x] Add automated tests for OSS module.
• [x] Remove old OSS and Kubecost modules.

Which issue(s) this PR fixes:

Fixes #

Quality checks

• [x] My content adheres to the style guidelines
• [x] I ran make test module="<module>" it was successful (see https://github.com/aws-samples/eks-workshop-v2/blob/main/docs/automated_tests.md)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

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