Remove Newtonsoft.Json from the shared framework

[natemcmaster]

The following shared-framework libraries pull in Newtonsoft.Json:

• - Microsoft.AspNetCore.Mvc.ViewFeatures
• - Microsoft.Extensions.Configuration.Json
• - Microsoft.Extensions.DependencyModel
• - Microsoft.IdentityModel.JsonWebTokens
• - Microsoft.AspNetCore.SignalR.Protocols.Json
• - Microsoft.AspNetCore.Authentication.OAuth
• - Microsoft.Extensions.Logging.EventSource

These assemblies and dependencies need to be updated to remove their dependency on Newtonsoft.Json.

[natemcmaster]

Tracking external issues:

• https://github.com/dotnet/core-setup/issues/3311
• Remove dependency on Newtonsoft.Json from Config.Json extensions#568
• Replace the dependency on Newtonsoft.Json with new .NET Json APIs AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet#1060
• Remove Newtonsoft.Json dependency from EventSource logger extensions#1013

Internal changes needed:

• @Tratcher - update Microsoft.AspNetCore.Authentication.OAuth
• @rynowak @mkArtakMSFT - we need to update Microsoft.AspNetCore.Mvc.ViewFeatures to make sure it doesn't pull in Newtonsoft.Json.
• Update our dependency on IdentityModel.

[natemcmaster]

Also adding @mkArtakMSFT to help with MVC's dependency on Json.net and myself to coordinate with partners on getting Json.net removed.

[natemcmaster]

Pushing out to preview3. We are still blocked on https://github.com/dotnet/core-setup/issues/3311 and dotnet/extensions#568