feat: Add Compose service name to Kibana's cert names

Allows the Fleet server to establish a trusted connection to Kibana when
the Kibana server has TLS enabled and Fleet uses the Compose service
name as host name.

extensions/fleet/fleet-compose.yml

@@ -28,6 +28,8 @@ services:
       FLEET_URL: https://fleet-server:8220
       FLEET_SERVER_CERT: /usr/share/elastic-agent/fleet-server.crt
       FLEET_SERVER_CERT_KEY: /usr/share/elastic-agent/fleet-server.key
+      # Use the HTTPS scheme if the Kibana server has TLS enabled (disabled by default)
+      #KIBANA_HOST: https://kibana:5601
       ELASTICSEARCH_HOST: https://elasticsearch:9200
       ELASTICSEARCH_CA: /usr/share/elastic-agent/ca.crt
       # Fleet plugin in Kibana

tls/instances.yml

@@ -17,7 +17,7 @@ instances:
   - kibana.127.0.0.1.nip.io    # Examples of resolvable domains.
   - kibana.127.0.0.1.sslip.io  #
   - localhost
-  - kibana
+  - kibana                     # resolved by Fleet, if configured to use the Compose service name
   ip:
   - 127.0.0.1
   - ::1