Visual Studio 2017 Azure Function Template does not have files like - run.csx or project.json
This is intended. Azure Functions team changed the way you develop and deploy Function Apps in Visual Studio 2017. Now, it's basically a compiled class library, with functions being static methods with proper attributes.
You should not be editing function.json manually anymore; instead use WebJob SDK attributes. Packages management is done the normal .NET way via NuGet packages.
The "old way" still works from within Azure portal for quick prototyping and experiments, but Visual Studio won't support it anymore.