feat(power): Allow user to manage system power states

User is put into the 'power' group, and everyone in the group can
interact with system power events (hibernate, suspend, reboot, shutdown,
halt, etc).

books/void_wayland.yaml

@@ -99,3 +99,30 @@
       ## TODO: Enable its start in river init script
       #
       # TODO: Find way to install and enable pipewire-roc-sink module (and enable ~/.config/pipewire/pipewire.conf.d/roc-sink.conf)
+
+
+- name: Allow user to manage system power
+  hosts: target_system
+  become: true
+  tags:
+    - power
+  tasks:
+    - name: Ensure user group "power" exists
+      ansible.builtin.group:
+        name: power
+        state: present
+
+    - name: Put user in power group
+      ansible.builtin.user:
+        name: "{{ user_name }}"
+        groups: [power]
+        append: true
+
+    - name: Enable power management for power group
+      ansible.builtin.copy:
+        content: "%power ALL=(ALL) NOPASSWD: /usr/bin/halt, /usr/bin/poweroff, /usr/bin/reboot, /usr/bin/shutdown, /usr/bin/zzz, /usr/bin/ZZZ"
+        dest: "/etc/sudoers.d/20-wheel"
+        owner: root
+        group: root
+        mode: 0644
+        force: true