add secret for hoarder

hosts/server/secrets/default.nix

@@ -16,6 +16,7 @@
       cloudflare-dns-token = { path = "/etc/cloudflare/dnskey.txt"; };
       nextcloud-pwd = { path = "/etc/nextcloud/pwd.txt"; };
       adguard-pwd = { };
+      hoarder = { };
     };
   };
 }