Add Config to set output serializer to System.Text.Json

What problem would the feature you’re requesting solve? Please describe.

Solves the problem that input serializer and output serializer are different. Function v3 uses System.Text.Json as input serializer and Newtonsoft.Json as output serializer. (#5299)

When sharing a Domain Model with an ASP.NET Core application, different serializers can cause compatibility issues.

Describe the solution you’d like

I need to change the output serializer to System.Text.Json.

Describe alternatives you’ve considered

There is a way to configure all applications to use Newtonsoft.Json. However, it does not match the current trend of .NET Core.

Additional context

https://github.com/Azure/azure-functions-host/blob/v3.x/src/WebJobs.Script.WebHost/WebHostServiceCollectionExtensions.cs#L75

[snapfisher]

So for .Net 6 will this functionality be available for all c# functions or only the isolated process functions?

[abouroubi]

Is there any news on this ? Now that .NET 6 us supported and the v4 is out