OTLP collector monitoring and Grafana/dashboards improvements

[jangaraj]

Changes

Please provide a brief description of the changes here.

• all dashboards configured to the last 15min
• dashboard "Opentelemetry Collector" updated from https://grafana.com/grafana/dashboards/15983-opentelemetry-collector/
• dashboard "Opentelemetry Collector Data Flow" deleted - it provides metrics visualized by "Opentelemetry Collector" dashboard
• default Grafana home is /grafana/dashboards/f/demo/?orgId=1 - dashboards in Demo folder
• "Demo Dashboard" updated
• configured static uid and severity field for Opensearch datasource
• used OTLP exporter for OTEL collector metrics
• scraping of OTEL collector metric from Prometheus disabled (collector is pushing own metrics)

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[puckpuck]

This looks good, but a couple of small changes we need to make.

[puckpuck]

I had to change line 1030 of demo-dashboard.json to read this:

"regex": "/.*service.name=\\\"([^\\\"]+)\\\".*/",

Replaces the _ with a .. That change should work with service_name and service.name for the label key.

[julianocosta89]

@jangaraj I noticed that we have a couple of duplicated tiles in the Collector Dashboard:

[jangaraj]

@julianocosta89 Could you provide more details, please? I don't see any duplication in your screenshot. thx.