Add Ansible playbook to configure PiKVM

Add Nix shell to flake
Monitor PiKVM with Prometheus
Serve Prometheus on /

ansible/roles/pikvm/tasks/main.yml

@@ -0,0 +1,20 @@
+---
+- name: Mount filesystem as read-write
+  ansible.builtin.command: rw
+  vars:
+    root_mount: "{{ ansible_mounts | selectattr('mount', 'equalto', '/') | first }}"
+  when: "'ro' in root_mount.options.split(',')"
+
+- name: Install Tailscale
+  community.general.pacman:
+    name: tailscale-pikvm
+    state: latest
+
+- name: Enable Tailscale
+  ansible.builtin.systemd_service:
+    name: tailscaled
+    state: started
+    enabled: true
+
+- name: Mount filesystem as read-only
+  ansible.builtin.command: ro