added caddy provider support

ansible/plays/machine_setup/templates/Caddyfile.j2

@@ -0,0 +1,14 @@
+# {{ ansible_managed }}
+#
+# This file only seeds Caddy's initial configuration: the admin API listener
+# that OpenTofu talks to. Reverse-proxy routes are managed by the caddy module
+# via the admin API (caddy_proxies in terraform.tfvars); Caddy autosaves those
+# changes and the systemd unit starts with --resume, so API-applied config
+# survives restarts and this file is ignored once an autosave exists.
+#
+# To re-seed from this file (e.g. after changing the admin listener), delete
+# /var/lib/caddy/.config/caddy/autosave.json and restart caddy.
+{
+	admin {{ caddy_admin_listen }}
+}
+}