[ubuntu] Rename build scripts (#8866)

* [ubuntu] Rename build scripts

* [ubuntu] Change reboot to inline shell

* [ubuntu] Move disk space validation to pester tests

* [ubuntu] Rename helper and tests files

* [ubuntu] Changes to cleanup, post-deployment and r scripts

images/ubuntu/scripts/build/install-heroku.sh

@@ -0,0 +1,21 @@
+#!/bin/bash -e
+################################################################################
+##  File:  install-heroku.sh
+##  Desc:  Install Heroku CLI. Based on instructions found here: https://devcenter.heroku.com/articles/heroku-cli
+################################################################################
+
+## Install Heroku CLI
+
+# add heroku repository to apt
+echo "deb https://cli-assets.heroku.com/channels/stable/apt ./" > /etc/apt/sources.list.d/heroku.list
+
+# install heroku's release key for package verification
+curl https://cli-assets.heroku.com/channels/stable/apt/release.key | apt-key add -
+
+# install heroku
+apt-get update -y && apt-get install -y heroku
+
+# remove heroku's apt repository
+rm /etc/apt/sources.list.d/heroku.list
+
+invoke_tests "Tools" "Heroku"