[AOT] Publish gRPC app as Native AOT with no warnings

[JamesNK]

• Fix ASP.NET Core runtime AOT warnings [AOT] Fix runtime warnings #45604
• Fix gRPC AOT warnings Enable AOT analysis and fix warnings grpc/grpc-dotnet#1924
• Fix Google.Protobuf AOT warnings Fix .NET Native AOT warnings in Protobuf reflection protocolbuffers/protobuf#11128
• Update grpc-dotnet to use fixed Google.Protobuf
• Update ASP.NET Core gRPC template to use fixed grpc-dotnet
• External warnings are fixed [AOT] Meta issue for warnings from outside of aspnetcore #45911
• Update ASP.NET Core gRPC template to have a -aot option to enable native AOT at project creation time