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/kubespray-defaults/tasks/main.yaml

@@ -5,6 +5,19 @@
   tags:
     - always
 
+- name: "Set up proxy environment"
+  set_fact:
+    proxy_env:
+      http_proxy: "{{ http_proxy | default ('') }}"
+      HTTP_PROXY: "{{ http_proxy | default ('') }}"
+      https_proxy: "{{ https_proxy | default ('') }}"
+      HTTPS_PROXY: "{{ https_proxy | default ('') }}"
+      no_proxy: "{{ no_proxy | default ('') }}"
+      NO_PROXY: "{{ no_proxy | default ('') }}"
+  no_log: true
+  tags:
+    - always
+
 # do not run gather facts when bootstrap-os in roles
 - name: set fallback_ips
   import_tasks: fallback_ips.yml