setup/teardown test env and test machines

[sonyafenge]

Part of issue #58:

1. ./hack/test-setup.sh

export SIM_NUM=2 CLIENT_NUM=4 SERVER_NUM=1 INSTANCE_PREFIX=sonya-grs
./hack/test-setup.sh
./hack/test-teardown.sh

2. By default, this script is using machine: sonya-grs-test-template as client image; machine: sonya-grs-resourcemanagement as server image. Any update for git or config, please follow the steps below:

start these two machines and update any changing. Then ensure these two machines are in "shutdown" state before move to next step;

run the command below, which will delete all existing image and regenerate image, and then run ./hack/test-setup.sh

export SERVERIMAGE_AUTO_DELETE=true SIMIMAGE_AUTO_DELETE=true CLIENTIMAGE_AUTO_DELETE=true
./hack/test-teardown.sh

3. simulator machines will be started with reserved_ip. and reserved_ip number should be greater then simulator vm number, these 5 ip has been reserved one GCP.

export SIM_NUM=5 
export SIM_RESERVED_IP="35.188.145.60,35.193.92.26,34.66.195.79,35.225.58.144,35.238.244.235"

[q131172019]

/LGTM