Traces Panel: Add new Traces Panel visualization (#47534)

* Panel

* Support tempo dash variables

* Support tempo explore variables

* Only show span links for explore

* Cleanup

* Added tests

* apply variables to search

* Tests for search variables

* Handling no data

* Interpolation and tests

* TracesPanel tests

* More tests

* Fix for backend test

* Manager integration test fix

* Traces doc and updated visualizations index doc

* Logs for this span

* Search, scrollToTop, other improvements

* Refactor to extract common code

* Removed TopOfViewRefType optional

* Remove topOfViewRef optional

* Removed another optional and fixed tests

* Test

* Only show search bar if trace

* Support traces panel in add to dashboard

* Self review

* Update betterer

* Linter fixes

* Updated traces doc

* Ahh, moved the for more info too

* Updated betterer.results

* Added new icon

* Updated expectedListResp.json

docs/sources/visualizations/_index.md

@@ -27,6 +27,7 @@ Grafana offers a variety of visualizations to support different use cases. This
   - [Table]({{< relref "./table/_index.md" >}}) is the main and only table visualization.
   - [Logs]({{< relref "./logs-panel.md" >}}) is the main visualization for logs.
   - [Node Graph]({{< relref "./node-graph.md" >}}) for directed graphs or networks.
+  - [Traces]({{< relref "./traces.md" >}}) is the main visualization for traces.
 - Widgets
   - [Dashboard list]({{< relref "./dashboard-list-panel.md" >}}) can list dashboards.
   - [Alert list]({{< relref "./alert-list-panel.md" >}}) can list alerts.

docs/sources/visualizations/traces.md

@@ -0,0 +1,19 @@
++++
+title = "Traces"
+keywords = ["grafana", "dashboard", "documentation", "panels", "traces"]
+weight = 850
++++
+
+# Traces panel
+
+> **Note:** This panel is currently in beta. Expect changes in future releases.
+
+_Traces_ are a visualization that enables you to track and log a request as it traverses the services in your infrastructure.
+
+For more information about traces and how to use them, refer to the following documentation:
+
+- [What are traces](https://grafana.com/docs/grafana-cloud/traces)
+- [Tracing in expliore]({{< relref "../explore/trace-integration.md" >}})
+- [Getting started with Tempo](https://grafana.com/docs/tempo/latest/getting-started)
+
+{{< figure src="/static/img/docs/explore/explore-trace-view-full-8-0.png" class="docs-image--no-shadow" max-width= "900px" caption="Screenshot of the trace view" >}}