Add Linux dashboard (#2395)

* Add Linux dashboard

* Add Linux dashboard

* WIP

* WIP

* WIP

---------

Co-authored-by: Juliano Costa <julianocosta89@outlook.com>

Author: cyrille-leclerc

CHANGELOG.md

@@ -88,6 +88,8 @@ the release.
 * [prometheus /grafana] Add alerting demo through the `CartAddItemHighLatency`
   alert rule
   [#2401](https://github.com/open-telemetry/opentelemetry-demo/pull/2401)
+* [prometheus / grafana] Add Linux monitoring dashboard
+  [#2395](https://github.com/open-telemetry/opentelemetry-demo/pull/2395)
 
 ## 2.0.2