Sync ConfigurationSchemaGenerator code from dotnet/runtime

[eerhardt]

With #1383, we are using code from https://github.com/dotnet/runtime/tree/main/src/libraries/Microsoft.Extensions.Configuration.Binder/gen. This is currently manually copied from dotnet/runtime. We should enable an automated sync that creates a PR automatically when dotnet/runtime updates.

cc @joperezr @sebastienros

[davidfowl]

Putting in the backlog.