caddy: add block_non_private_ips snippet

blocks ips not in tailnet or in local network from accessing services
using `important block_non_private_ips` in their caddy config

modules/services/caddy.nix

@@ -22,6 +22,12 @@
     
     services.caddy = {
       enable = true;
+      extraConfig = ''
+      (block_non_private_ips) {
+        @non_private_ips not remote_ip 100.64.0.0/10 fd7a:115c:a1e0::/48 private_ranges
+        abort @non_private_ips
+      }
+      '';
     };
 
     security.acme = {