[docs] Add example tracing infrastructure (#1866)

This adds an example on how to get Grafana Tempo up to receive spans as
well as Grafana itself to view them.

I've added this as a separate Tracing doc in the installation guide as
the Advanced one was starting to get rather full.

Fixes: #1791

example/tracing/docker-compose.yaml

@@ -0,0 +1,24 @@
+version: "3"
+services:
+  tempo:
+    image: docker.io/grafana/tempo:2.1.1
+    command: [ "-config.file=/etc/tempo.yaml" ]
+    volumes:
+      - ./tempo.yaml:/etc/tempo.yaml
+      - ./tempo-data:/tmp/tempo
+    ports:
+      - "3200:3200"  # tempo
+      - "9095:9095"  # tempo grpc
+      - "4317:4317"  # otlp grpc
+
+  grafana:
+    image: docker.io/grafana/grafana:9.5.2
+    volumes:
+      - ./grafana-datasources.yaml:/etc/grafana/provisioning/datasources/datasources.yaml
+    environment:
+      - GF_AUTH_ANONYMOUS_ENABLED=true
+      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
+      - GF_AUTH_DISABLE_LOGIN_FORM=true
+      - GF_FEATURE_TOGGLES_ENABLE=traceqlEditor
+    ports:
+      - "3000:3000"