Publish echo resource as Microsoft.DSC.Debug/Echo

[michaeltlombardi]

Summary of the new feature / enhancement

As a user, I want to be able to use a non-acting resource to see how configuration functions and group resources behave.

As a documentarian, I want to write executable examples that show users how configuration functions and group resources behave.

As a user, I want to be able to debug complex cases in my configuration by echoing data without having to write custom resources or rely on logging in the resources I consume.

Proposed technical implementation details (optional)

We have the Test/Echo resource implemented, but it's not published in the build and would be useful if published fully as a debug resource. Examples in the reference documentation depend on the echo resource to show behavior, but users who don't build from source can't execute the examples.