Add endpoints v2 sample

[broady]

Python
https://github.com/GoogleCloudPlatform/python-docs-samples/tree/master/managed_vms/endpoints

Go
https://github.com/GoogleCloudPlatform/golang-samples/tree/master/docs/managed_vms/endpoints

PHP
GoogleCloudPlatform/php-docs-samples#95

@jmdobry @jonparrott

[jmdobry]

Fixed by #105