Updated documentation to include details on using Azure storage for backup & restore.
Updated documentation to include details on using Azure storage for backup & restore.

Mahesh-MSFT/service-fabric-dotnet-web-reference-app,alexmullans/service-fabric-dotnet-multisln-backend,Azure-Samples/service-fabric-dotnet-web-reference-app,Mahesh-MSFT/service-fabric-dotnet-web-reference-app,Azure-Samples/service-fabric-dotnet-web-reference-app