[Dashboard Request] Add a New Dashboard - Otel agent metrics

[RenatoDourad0]

Dashboard Name:
Otel agent metrics

Metrics:
https://opentelemetry.io/docs/collector/internal-telemetry/#basic-level-metrics

Target System:
opentelemetry collector

Additional Features/Widgets:
Based on a dashboard similar to this one but with an additional variable for the collector name. This allows filtering multiple collectors by name within a single dashboard.

Use Case:
It helps monitor how individual collectors are performing.