Overhaul local user management

Fix user deletion on removal/reassignment
Improve efficiency and cross platform support

playbooks/deploy-sshkeys.yml

@@ -13,6 +13,7 @@
             state: directory
             path: /home/{{ item.name }}/.ssh
           loop: "{{ local_users | difference([None]) }}"
+
         - name: Put keys on remote
           when: item.keys != []
           authorized_key: