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/prometheus.yml

@@ -0,0 +1,15 @@
+---
+global:
+  scrape_interval: 60s
+
+scrape_configs:
+  - job_name: tempo
+    static_configs:
+      - targets: ['tempo:3200']
+        labels:
+          instance: tempo
+  - job_name: aurweb
+    static_configs:
+      - targets: ['fastapi:8000']
+        labels:
+          instance: aurweb