Use TFTEST_E2E_ instead of TF_VAR variables

Use of TF_VAR variables modified results of `tests/examples` and
required setting different environment to run `tests/examples` and
`tests/examples_e2e` tests. No both can be run using the same
environment.

tools/create_e2e_sandbox.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+# Copyright 2023 Google LLC
+#
+# 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_e2e_sandbox.sh <directory>
+#
+# creates end-to-end tests sandbox in given directory, in result you get:
+# 1. <directory>/infra with terraform module applied with all prerequisites provisioned
+# 2. <directory> with empty main.tf file, where you can paste any example and manually run any terraform command
+#
+# You need to have all the environment variables set up only during running of this script. Their values will be
+# preserved in terraform.tfvars file, so if you want to destroy / make changes to the infra module, all should work
+#
+# You can rerun this script on existing directory, this will update all the (terraform) files, but will reuse the existing
+# project name and folder name to reduce time to update
+#
+set -e
+
+DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+DEST=$1
+INFRA="${DEST}/infra"
+TIMESTAMP=$(date +%s)
+
+mkdir -p "${DEST}" "${INFRA}"
+
+ln -sfT "${DIR}" "${DEST}/fabric"
+
+SETUP_MODULE="${DIR}/tests/examples_e2e/setup_module"
+cp "${SETUP_MODULE}/main.tf" "${SETUP_MODULE}/variables.tf" "${SETUP_MODULE}/e2e_tests.tfvars.tftpl" "${INFRA}"
+
+cp "${DIR}/tests/examples/variables.tf" "${DEST}"
+
+if [ ! -f "${INFRA}/randomizer.auto.tfvars" ] ; then
+  echo "suffix=0" > "${INFRA}/randomizer.auto.tfvars"
+  echo "timestamp=${TIMESTAMP}" >> "${INFRA}/randomizer.auto.tfvars"
+fi
+
+# TODO correct environment variable prefix
+export | sed -e 's/^declare -x //' | grep '^TFTEST_E2E_' | sed -e 's/^TFTEST_E2E_//' > "${INFRA}/terraform.tfvars"
+(
+  cd "${INFRA}"
+  terraform init
+  terraform apply -auto-approve
+  ln -sfT "${INFRA}/e2e_tests.tfvars" "${DEST}/e2e_tests.auto.tfvars"
+)
+
+tocuh "${DEST}/main.tf"