Update template samples

[JoshLove-msft]

We should add some example sample md files that demonstrate the recommended sample structure to the template directory.
Example: https://github.com/Azure/azure-sdk-for-net/tree/master/sdk/eventgrid/Azure.Messaging.EventGrid/samples

[jsquire]

The template project has an example set of sample files, including a README, a sync sample, and an async sample. Closing this out.