Add observability platform Ansible project

Deploys the Grafana stack (Prometheus/Alertmanager/Loki/Tempo/Grafana with
Alloy as collector) and the ELK stack (Filebeat/Logstash/Elasticsearch/
Kibana) via Docker Compose on a target host. External to the application
repo, pre-built by the mentor.

ansible/roles/observability/templates/grafana-stack/config/prometheus/prometheus.yml.j2

@@ -0,0 +1,43 @@
+global:
+  scrape_interval: 15s
+  evaluation_interval: 15s
+
+rule_files:
+  - /etc/prometheus/rules/*.yml
+
+alerting:
+  alertmanagers:
+    - static_configs:
+        - targets: ["alertmanager:9093"]
+
+scrape_configs:
+  - job_name: prometheus
+    static_configs:
+      - targets: ["prometheus:9090"]
+
+  - job_name: node-exporter
+    static_configs:
+      - targets: ["node-exporter:9100"]
+
+  - job_name: loki
+    static_configs:
+      - targets: ["loki:3100"]
+
+  - job_name: tempo
+    static_configs:
+      - targets: ["tempo:3200"]
+
+  - job_name: alloy
+    static_configs:
+      - targets: ["alloy:12345"]
+
+  - job_name: grafana
+    static_configs:
+      - targets: ["grafana:3000"]
+
+{% for job in prometheus_extra_scrape_jobs %}
+  - job_name: "{{ job.job_name }}"
+    static_configs:
+      - targets: {{ job.targets | to_json }}
+{% endfor %}
+