Add sanoid Ansible role for ZFS snapshots and replication

Replaces manually deployed config files with a fully idempotent role:
installs sanoid, templates sanoid.conf and syncoid service/timer from
variables, enables both systemd timers. Removes static proxmox/sanoid.*
files. README rebuild section updated accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ansible/roles/sanoid/handlers/main.yml

@@ -0,0 +1,12 @@
+---
+- name: Restart sanoid timer
+  ansible.builtin.systemd:
+    name: sanoid.timer
+    state: restarted
+    daemon_reload: true
+
+- name: Restart syncoid timer
+  ansible.builtin.systemd:
+    name: syncoid.timer
+    state: restarted
+    daemon_reload: true