Add KVM hypervisor playbook to contrib

Optional Ansible playbook for preparing a host for running Kargo.
This includes creation of a user account, some basic packages,
and sysctl values required to allow CNI networking on a libvirt network.

contrib/kvm-setup/roles/kvm-setup/tasks/user.yml

@@ -0,0 +1,46 @@
+---
+- name: Create user {{ k8s_deployment_user }}
+  user:
+    name: "{{ k8s_deployment_user }}"
+    groups: adm
+    shell: /bin/bash
+
+- name: Ensure that .ssh exists
+  file:
+    path: "/home/{{ k8s_deployment_user }}/.ssh"
+    state: directory
+    owner: "{{ k8s_deployment_user }}"
+    group: "{{ k8s_deployment_user }}"
+
+- name: Configure sudo for deployment user
+  copy:
+    content: |
+      %{{ k8s_deployment_user }} ALL=(ALL) NOPASSWD: ALL
+    dest: "/etc/sudoers.d/55-k8s-deployment"
+    owner: root
+    group: root
+    mode: 0644
+
+- name: Write private SSH key
+  copy:
+    src: "{{ k8s_deployment_user_pkey_path }}"
+    dest: "/home/{{ k8s_deployment_user }}/.ssh/id_rsa"
+    mode: 0400
+    owner: "{{ k8s_deployment_user }}"
+    group: "{{ k8s_deployment_user }}"
+  when: k8s_deployment_user_pkey_path is defined
+
+- name: Write public SSH key
+  shell: "ssh-keygen -y -f /home/{{ k8s_deployment_user }}/.ssh/id_rsa \
+            > /home/{{ k8s_deployment_user }}/.ssh/authorized_keys"
+  args:
+    creates: "/home/{{ k8s_deployment_user }}/.ssh/authorized_keys"
+  when: k8s_deployment_user_pkey_path is defined
+
+- name: Fix ssh-pub-key permissions
+  file:
+    path: "/home/{{ k8s_deployment_user }}/.ssh/authorized_keys"
+    mode: 0600
+    owner: "{{ k8s_deployment_user }}"
+    group: "{{ k8s_deployment_user }}"
+  when: k8s_deployment_user_pkey_path is defined