Create a load testing EPP client (#2415)

* Create a load testing EPP client.

This code is mostly based off of what was used for a past EPP load testing client that can be found in Google3 at https://source.corp.google.com/piper///depot/google3/experimental/users/jianglai/proxy/java/google/registry/proxy/client/

I modified the old client to be open-source friendly and use Gradle.

For now, this only performs a login and logout command, I will further expand on this in later PRs to add other EPP commands so that we can truly load test the system.

* Small changes

* Remove unnecessary build dep

* Add gradle build tasks

* Small fixes

* Add an instances setUp and cleanUp script

* More modifications to instance setup scripts

* change to ubuntu instance

* Add comment to make ssh work

load-testing/instanceSetUp.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+# Copyright 2024 The Nomulus Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Create the instances - modify this number for the amount of instances you
+# would like to use for your load test
+gcloud compute instances create loadtest-{1..2} --machine-type g1-small \
+--image-family ubuntu-2204-lts --image-project ubuntu-os-cloud --zone us-east4-a
+
+sleep 10
+
+# Get all the created load tests instances
+HOSTS=$(gcloud compute instances list | awk '/^loadtest/ { print $5 }')
+
+#Install rsync and Java - Retry is needed here since ssh connection will fail until instances are fully provisioned
+for host in $HOSTS;
+  do
+    for i in {1..60}; do
+      if ssh $host 'sudo apt-get -y update &&
+                    sudo apt-get -y upgrade &&
+                    sudo apt-get -y install rsync &&
+                    sudo apt-get -y install openjdk-21-jdk'; then
+        break
+      else
+        sleep 5
+      fi
+    done
+  done