feat(docker): add full grafana, prometheus, tempo setup for local dev

This is a very useful stack for local development as well, by allowing
to easily access a local grafana instance and look at the accessed
endpoints, query usage and durations etc.
As a nice side effect this also makes sure we have an easy way to
actually test any changes to the opentelemetry integration in an actual
environment instead of just listening to a raw socket.

docker/config/grafana/datasources/datasource.yml

@@ -0,0 +1,42 @@
+---
+apiVersion: 1
+
+deleteDatasources:
+  - name: Prometheus
+  - name: Tempo
+
+datasources:
+  - name: Prometheus
+    type: prometheus
+    uid: prometheus
+    access: proxy
+    url: http://prometheus:9090
+    orgId: 1
+    editable: false
+    jsonData:
+      timeInterval: 1m
+  - name: Tempo
+    type: tempo
+    uid: tempo
+    access: proxy
+    url: http://tempo:3200
+    orgId: 1
+    editable: false
+    jsonData:
+      tracesToMetrics:
+        datasourceUid: 'prometheus'
+        spanStartTimeShift: '1h'
+        spanEndTimeShift: '-1h'
+      serviceMap:
+        datasourceUid: 'prometheus'
+      nodeGraph:
+        enabled: true
+      search:
+        hide: false
+      traceQuery:
+        timeShiftEnabled: true
+        spanStartTimeShift: '1h'
+        spanEndTimeShift: '-1h'
+      spanBar:
+        type: 'Tag'
+        tag: 'http.path'