Parameter constraint samples for HOT hello world

Adding example for parameter validation constraints to HOT hello world
template to show new syntax and features for parameter constraints in
HOT.

This change depends on changes in the heat github repository, which
need to be completed so this new template can be processed.

Contributes to blueprint hot-parameters

Change-Id: I720f22795c94e4ceacc9ebe030929f9b58e981e9

hot/hello_world.yaml

@@ -12,9 +12,33 @@ parameters:
   InstanceType:
     type: string
     description: Instance type for the instance to be created
+    default: m1.small
+    constraints:
+      - allowed_values: [m1.tiny, m1.small, m1.large]
+        description: Value must be one of 'm1.tiny', 'm1.small' or 'm1.large'
   ImageId:
     type: string
     description: ID of the image to use for the instance
+  # parameters below are not used in template, but are for verifying parameter
+  # validation support in HOT
+  db_password:
+    type: string
+    description: Database password
+    hidden: true
+    constraints:
+      - length: { min: 6, max: 8 }
+        description: Password length must be between 6 and 8 characters
+      - allowed_pattern: "[a-zA-Z0-9]+"
+        description: Password must consist of characters and numbers only
+      - allowed_pattern: "[A-Z]+[a-zA-Z0-9]*"
+        description: Password must start with an uppercase character
+  db_port:
+    type: number
+    description: Database port number
+    default: 50000
+    constraints:
+      - range: { min: 40000, max: 60000 }
+        description: Port number must be between 40000 and 60000
 
 resources:
   my_instance: