docs: OpenTelemetry Collector Sandbox Tutorial (backport release-3.1.x)

[loki-gh-app]

Backport f4d58ab from #13745

---

This PR adds a new sandbox tutorial to the otel section of send-data. This tutorial teaches users how to send OTLP native logs via the Otel Collector to the native OTLP endpoint of Loki.

The tutorial can be tested here: https://killercoda.com/grafana-dev-testing/course/loki/otel-collector-getting-started

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR