Do not install docker for bench in offline mode

ansible/roles/bench-server/tasks/main.yml

@@ -55,27 +55,35 @@
     remote_src: yes
 
 - name: add docker key
-  when: not in_docker
+  when:
+    - not offline_mode | d(false)
+    - not in_docker | d(false)
   apt_key:
     url: https://download.docker.com/linux/debian/gpg
     state: present
 
 - name: add docker debian repository
-  when: not in_docker
+  when:
+    - not offline_mode | d(false)
+    - not in_docker | d(false)
   apt_repository:
     repo: "deb https://download.docker.com/linux/debian buster stable"
     state: present
     update_cache: yes
 
 - name: install docker
-  when: not in_docker
+  when:
+    - not offline_mode | d(false)
+    - not in_docker | d(false)
   apt:
     name: docker-ce
     state: latest
     update_cache: yes
 
 - name: generate docker image
-  when: not in_docker
+  when:
+    - not offline_mode | d(false)
+    - not in_docker | d(false)
   command:
     cmd: make build_docker_img
     chdir: /usr/share/ms-testing-suite