DEV-646 skip docker network removal by nightly cron job

roles/ansible-role-docker/tasks/main.yml

@@ -9,4 +9,4 @@
     name: "remove unused docker objects"
     minute: "0"
     hour: "1"
-    job: "docker system prune -af"
+    job: "docker system prune -af --filter label!=prune=disable"

roles/common/tasks/main.yml

@@ -236,6 +236,8 @@
 - name: "Create Docker network"
   community.docker.docker_network:
     name: "{{ item }}"
+    labels:
+      prune: disable
   when: docker_enabled
   loop:
     - front-tier