Get Started tutorial on types

[BillWagner]

Fixes #45114

Add a new day one interactive tutorial to explore how you create types in C#. This tutorial focuses on tuples and records, as the simplest data container types in C#. This is meant to be a day 1 exploration, so this tutorial assumes the reader hasn't acquired the SDK or other tools yet.

More types will be explored in tutorials in the "Fundamentals" section, when readers are assumed to have installed necessary tools.

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Internal previews

📄 File	🔗 Preview link
docs/csharp/toc.yml	Taken from https://github.com/dotnet/roslyn/wiki/Samples-and-Walkthroughs
docs/csharp/tour-of-csharp/tutorials/index.md	Interactive tutorials
docs/csharp/tour-of-csharp/tutorials/numbers-in-csharp.md	How to use integer and floating point numbers in C#
docs/csharp/tour-of-csharp/tutorials/tuples-and-types.md	docs/csharp/tour-of-csharp/tutorials/tuples-and-types