Add example of using native waitcondition resources

Adds a simple example of using the native WaitCondition and
WaitConditionHandle resources, which work in a similar way to
the CFN compatible ones, but with more relaxed validation of
data, and some additional helper attributes so you don't need
to remember how to write the curl call in the template unless
you need something unusual in the request.

Change-Id: I2686d07e882781e93949ded9dd260161e4514a3b
blueprint: native-waitcondition
Merge "Add example of using native waitcondition resources"