Adds Parameter Label to HOT spec and parameter schema

This change will add the ability to put a human readable label
in a HOT Template for each parameter. This label will be used
to provide a better form label in any user interface when
available.

Change-Id: I8d815d1cfceb71c1ea0a9907f2afeb06dc4fca09
Implements: blueprint add-parameter-label-to-template
Merge "Adds Parameter Label to HOT spec and parameter schema"