Convert OS specific packages to new format

Uses the logic introduced in the previous patch to convert all
kubernetes/preinstall/vars/* os specific files to the `pkgs`
dictionary.

Some niceties for devs:
- always validate the `pkgs` variable to catch mistakes in CI.
- ensure that `pkgs` is always sorted. This makes it easier to find the
  packages you're looking for.

roles/kubernetes/preinstall/tasks/0020-set_facts.yml

@@ -199,20 +199,6 @@
       supersede domain-name-servers {{ (nameservers | d([]) + cloud_resolver | d([])) | unique | join(', ') }};
   when: dns_early and not dns_late
 
-- name: Gather os specific variables
-  include_vars: "{{ item }}"
-  with_first_found:
-    - files:
-        - "{{ ansible_distribution | lower }}-{{ ansible_distribution_version | lower | replace('/', '_') }}.yml"
-        - "{{ ansible_distribution | lower }}-{{ ansible_distribution_release }}.yml"
-        - "{{ ansible_distribution | lower }}-{{ ansible_distribution_major_version | lower | replace('/', '_') }}.yml"
-        - "{{ ansible_distribution | lower }}.yml"
-        - "{{ ansible_os_family | lower }}.yml"
-        - defaults.yml
-      paths:
-        - ../vars
-      skip: true
-
 - name: Set etcd vars if using kubeadm mode
   set_fact:
     etcd_cert_dir: "{{ kube_cert_dir }}"

roles/kubernetes/preinstall/tasks/0040-verify-settings.yml

@@ -316,3 +316,15 @@
   when:
     - kube_apiserver_enable_admission_plugins is defined
     - kube_apiserver_enable_admission_plugins | length > 0
+
+- name: Verify that the packages list structure is valid
+  ansible.utils.validate:
+    criteria: "{{ lookup('file', 'pkgs-schema.json') }}"
+    data: "{{ pkgs }}"
+
+- name: Verify that the packages list is sorted
+  vars:
+    pkgs_lists: "{{ pkgs.keys() | list }}"
+  assert:
+    that: "pkgs_lists | sort == pkgs_lists"
+    fail_msg: "pkgs is not sorted: {{ pkgs_lists | ansible.utils.fact_diff(pkgs_lists | sort) }}"