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/bootstrap-os/tasks/bootstrap-fedora.yml

@@ -6,7 +6,6 @@
   register: need_bootstrap
   failed_when: false
   changed_when: false
-  environment: {}
   tags:
     - facts
 
@@ -24,7 +23,6 @@
 - name: Install python3 on fedora
   raw: "dnf install --assumeyes --quiet python3"
   become: true
-  environment: {}
   when:
     - need_bootstrap.rc != 0