SEMCON-763: Adding otelcol metrics to the otel metrics metadata

[fpddog]

What does this PR do?
Updates the metadata for the OTel Collector metrics with some missing metrics.
See: https://opentelemetry.io/docs/collector/internal-telemetry/

Motivation
The latest changes in the Prometheus receiver broke the names of the metrics being emitted by the collector. We need to use equiv_otel to union the old metric names with the new metric names, to make sure that our OOTB dashboards work for all customers. This requires being able to capture the metric equivalences in the Semantic Core, which itself relies on the metrics metadata files. We need the info in these files to be up to date for the equivalences to be accurate.

More info in https://datadoghq.atlassian.net/browse/SEMCON-752

Incident slack channel: #incident-35946

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged