Cleanup of kubernetes/preinstall (#11010)

* Move fedora ansible python install to bootstrap-os

* /bin/dir is set in bootstrap-os

* Removing ansible_os_family workarounds

Support for these distributions was merged in Ansible, no need to
override it ourselves now.
https://github.com/ansible/ansible/pull/69324 openEuler
https://github.com/ansible/ansible/pull/77275/ UnionTech OS Server 20
https://github.com/ansible/ansible/pull/78232/ Kylin

* Don't unconditionnaly set VARIANT_ID=coreos in os-release

WTF, this is so wrong.
Furthermore, is_fedora_coreos is already handled in boostrap-os

* Handle Clearlinux generically

Followup of 4eec302e86 (since we're using
package module anyway, let's get rid of the custom task)

roles/kubernetes/preinstall/tasks/0070-system-packages.yml

@@ -48,20 +48,6 @@
     - ansible_os_family == "RedHat"
     - not is_fedora_coreos
 
-- name: Install python3-dnf for latest RedHat versions
-  command: dnf install -y python3-dnf
-  register: dnf_task_result
-  until: dnf_task_result is succeeded
-  retries: 4
-  delay: "{{ retry_stagger | random + 3 }}"
-  when:
-    - ansible_distribution == "Fedora"
-    - ansible_distribution_major_version | int >= 30
-    - not is_fedora_coreos
-  changed_when: False
-  tags:
-    - bootstrap-os
-
 - name: Install epel-release on RHEL derivatives
   package:
     name: epel-release
@@ -86,14 +72,6 @@
   until: pkgs_task_result is succeeded
   retries: "{{ pkg_install_retries }}"
   delay: "{{ retry_stagger | random + 3 }}"
-  when: not (ansible_os_family in ["Flatcar", "Flatcar Container Linux by Kinvolk", "ClearLinux"] or is_fedora_coreos)
+  when: not (ansible_os_family in ["Flatcar", "Flatcar Container Linux by Kinvolk"] or is_fedora_coreos)
   tags:
     - bootstrap-os
-
-- name: Install ipvsadm for ClearLinux
-  package:
-    name: ipvsadm
-    state: present
-  when:
-    - ansible_os_family in ["ClearLinux"]
-    - kube_proxy_mode == 'ipvs'