customdata example a little too trivial

The example given in https://github.com/Azure/azure-quickstart-templates/tree/master/101-vm-customdata/ leaves the user wondering what to do if they have a customData value that has more than one line. It would be nice to have an example that demonstrates how to have a cloud-init.yaml file and pass it in as customData.

Start with the 101-vm-customdata example linked in the issue and review how its customData value is currently supplied. Add a corresponding cloud-init.yaml example showing a multi-line value passed as customData. Done means the quickstart template clearly demonstrates this use case.

Written by the indexing model from the issue text.