Add a role for Jitsi in Docker Compose

We need this role to follow the recommended deployment approach from https://jitsi.github.io/handbook/docs/devops-guide/devops-guide-docker/

This role enables us to keep our config and customizations separate from releases of the Compose setup the Jitsi project publishs.

roles/jitsi/templates/compose.override.yaml.j2

@@ -0,0 +1,40 @@
+# {{ ansible_managed }}
+# Services in addition to the ones of the docker-jitsi-meet release.
+
+# Docker Compose explicitly disables IPv6 for networks not enabling it, overriding the
+# daemon's default-network-opts.
+networks:
+  meet.jitsi:
+    enable_ipv6: true
+
+services:
+{% if jitsi__turn %}
+  coturn:
+    image: docker.io/coturn/coturn:4.18.0
+    restart: unless-stopped
+    # Recommended by coturn, as Docker performs badly with large port ranges.
+    network_mode: host
+    # Needs to be able to read the certificate obtained by the web container.
+    user: "1000:1000"
+    command: ["-c", "/etc/coturn/turnserver.conf"]
+    volumes:
+      - {{ jitsi__base_dir }}/coturn/turnserver.conf:/etc/coturn/turnserver.conf:ro
+      - {{ jitsi__config_dir }}/storage/web/acme-certs/{{ jitsi__domain }}:/certs:ro
+    tmpfs:
+      - /var/lib/coturn
+{% endif %}
+{% if jitsi__prometheus_exporter %}
+  prometheus-jitsi-meet-exporter:
+    image: docker.io/systemli/prometheus-jitsi-meet-exporter:1.4.2
+    restart: unless-stopped
+    command: ["-videobridge-url", "http://jvb:8080/colibri/stats"]
+    ports:
+      - "9888:9888"
+    depends_on:
+      - jvb
+    networks:
+      meet.jitsi:
+{% endif %}
+{% if not (jitsi__turn or jitsi__prometheus_exporter) %}
+  {}
+{% endif %}