Only setup *_PROXY env variables where needed (#7095)

no_proxy is a pain to get right, and having proxy variables present causes issues
(k8s components get proxy configuration after upgrade, see #7100)

It's better to only configure what require proxy:
- the runtime (containerd/docker/crio)
- the package manager + apt_key
- the download tasks

Tested with the following clusters
- 4 CentOS 8 nodes
- 1 Ubuntu 20.04 node

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

roles/container-engine/docker/tasks/main.yml

@@ -74,6 +74,7 @@
   retries: 4
   delay: "{{ retry_stagger | d(3) }}"
   with_items: "{{ docker_repo_key_info.repo_keys }}"
+  environment: "{{ proxy_env }}"
   when: not (ansible_os_family in ["Flatcar Container Linux by Kinvolk", "RedHat", "Suse", "ClearLinux"] or is_ostree)
 
 - name: ensure docker-ce repository is enabled
@@ -95,6 +96,7 @@
   retries: 4
   delay: "{{ retry_stagger | d(3) }}"
   with_items: "{{ dockerproject_repo_key_info.repo_keys }}"
+  environment: "{{ proxy_env }}"
   when:
     - not (ansible_os_family in ["Flatcar Container Linux by Kinvolk", "RedHat", "Suse", "ClearLinux"] or is_ostree)
     - use_docker_engine is defined and use_docker_engine