Performance Enhancements, Package Updates, Bug Fixes

1) Used ExceptionHandlingScope in the EnsureConfigurationListInTenant function  so that only one call is made to the server instead of multiple calls. This will perform better.
2) changed the name of the config list from "OfficeAMSConfig" to "OfficeDevPnPConfig"
3) added JSON.NET NuGet package as project was not building without it.
4) Added check for trailing slash in the SetSiteLogo and UploadFiletoWeb functions. The SetSiteLogo function was failing due to incorrect double slash ( // ) being generated in the url.