Creating README.md for the project templates.
Creating README.md for the project templates.

This change creates a README.md file for the project templates for the extension, with instructions on how to develop the templates.
GoogleCloudPlatform/google-cloud-visualstudio,ivannaranjo/google-cloud-visualstudio,ILMTitan/google-cloud-visualstudio,ivannaranjo/google-cloud-visualstudio,GoogleCloudPlatform/google-cloud-visualstudio,ILMTitan/google-cloud-visualstudio,GoogleCloudPlatform/google-cloud-visualstudio,GoogleCloudPlatform/google-cloud-visualstudio,Deren-Liao/google-cloud-visualstudio,GoogleCloudPlatform/google-cloud-visualstudio,Deren-Liao/google-cloud-visualstudio,ivannaranjo/google-cloud-visualstudio,ILMTitan/google-cloud-visualstudio,Deren-Liao/google-cloud-visualstudio,ILMTitan/google-cloud-visualstudio,ILMTitan/google-cloud-visualstudio