feat(admin): add global message query route

crates/delta/src/routes/admin/mod.rs

@@ -0,0 +1,9 @@
+use revolt_rocket_okapi::revolt_okapi::openapi3::OpenApi;
+use rocket::Route;
+
+mod message_query;
+mod stats;
+
+pub fn routes() -> (Vec<Route>, OpenApi) {
+    openapi_get_routes_spec![stats::stats, message_query::message_query]
+}