refactor: move proxy to monorepo

backend/proxy/fixtures/hiddenRoute.template

@@ -0,0 +1,8 @@
+location {{{ route }}} {
+
+    # use our custom request limit and allow bursts
+    # deliver them with no queuing delay
+    limit_req zone=customstappslimit burst=20;
+
+    return 404;
+}