Ensure kubeadm doesn't use proxy (#7275)

* Move proxy_env to kubespray-defaults/defaults

There is no reasons to use set_facts here

Signed-off-by: Etienne Champetier <e.champetier@ateme.com>

* Ensure kubeadm doesn't use proxy

*_proxy variables might be present in the environment (/etc/environment, bash profile, ...)
When this is the case we end up with those proxy configuration in /etc/kubernetes/manifests/kube-*.yaml manifests

We cannot unset env variables, but kubeadm is nice enough to ignore empty vars
93d288e2a4/cmd/kubeadm/app/util/env.go (L27)

Signed-off-by: Etienne Champetier <e.champetier@ateme.com>

roles/kubespray-defaults/tasks/main.yaml

@@ -5,19 +5,6 @@
   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