feat: Add OTEL LINKERD to prod

[muruganishekar]

Relevant information

Promoting the Linkerd OTel entity definition (EXT:LINKERD) from staging to production
in the newrelic/entity-definitions repository.

New synthesis rules being added to prod

• ext_linkerd_otel (Metric) — composite identifier: k8s.cluster.name + linkerd_control_plane_ns
• ext_linkerd_otel_logs (Log) — same composite identifier, scoped to CP components
• ext_linkerd_otel_span (Span) — same composite identifier, scoped to CP components

New relationship rules being added to prod

• INFRA:KUBERNETESCLUSTER CONTAINS EXT:LINKERD (k8sClusterContainsExtLinkerdOtel)
• EXT:LINKERD MANAGES INFRA:KUBERNETES_DEPLOYMENT (extLinkerdManagesK8sDeploymentOtel)

Why?

Staging validation is complete (PRs #3117, #3147, #3210 merged).
The entity type is functioning correctly in staging; promoting to general availability.

Impact

New EXT:LINKERD entities will be synthesized for accounts sending OTel Linkerd
control-plane metrics/logs/spans. No existing entities are modified.

Api Review Board (ARB)

Pull requests with changes to this repository might need to be linked with an ARB ticket, which has to be approved before merging.

If you are an external contributor please contact New Relic Support.

What definition changes require ARB and which do not? Guide here.

If you are new to ARB process also check this.

ARB Jira ticket:
https://new-relic.atlassian.net/browse/NR-614300

Checklist

• I've read the guidelines and understand the acceptance criteria.
• The value of the attribute marked as identifier will be unique and valid.
• I've confirmed that my entity type wasn't already defined. If it is I'm providing an explanation above.
• I've linked an ARB ticket & received approval from API Review Board in order to make these changes

[entityBot]

beep boop bop.

I have found some errors processing these changes:

• No valid, approved ARB ticket found in the PR description. This PR has to be reviewed by the API Review Board, please include a link to the ticket of that review in the PR description. Check how to start the process here or reach #api-review-board channel in case of doubts

[entityBot]

⚠️ Review Required ⚠️

👋 This PR has seen no activity in over 3 days and is still awaiting approval from: @newrelic/OHAI

Please review or provide an update.