Update api: Template Upload
Update api: Template Upload

Using "vitrage template add --path /home/stack/my_new_template.yaml" to validate template,
this is a way to execute from the command line. In the api document, we should provide the specific
request method content of the http request

Change-Id: I0c58d3a3cc6714785f0109536d9f6978008328f1

openstack/vitrage,openstack/vitrage,openstack/vitrage