new: dev: provide ``get_container_network_ips`` to charms

bin/compose-core

@@ -774,6 +774,24 @@ get_running_containers_for_service() {
 export -f get_running_containers_for_service
 
 
+get_container_network_ips() {
+    local container="$1"
+    docker inspect "$container" \
+           --format='{{range $key, $val :=.NetworkSettings.Networks}}{{$key}}{{"\x00"}}{{$val.IPAddress}}{{"\x00"}}{{end}}'
+}
+export -f get_container_network_ips
+
+
+get_container_network_ip() {
+    local container="$1"
+    while read-0 network ip; do
+        printf "%s\0" "$network" "$ip"
+        break
+    done < <(get_container_network_ips "$container")
+}
+export -f get_container_network_ip
+
+
 ##
 ## Internal Process
 ##