feat: volsync is now a addon

Signed-off-by: Devin Buhl <devin@buhl.casa>

bootstrap/vars/addons.sample.yaml

@@ -50,3 +50,7 @@ discord_template_notifier:
   # so it's easier to keep track of changes.
   enabled: false
   webhook_url: # Discord webhook url
+
+# https://github.com/backube/volsync
+volsync:
+  enabled: false