Authoring support for C# built-in types to WinRT types

[manodasanW]

• Authoring support for mapping C# built-in types to WinRT types (both as part of type reference in param / return type, but also for implementing them)
• Added support for generics
• Added support for arrays
• Various bug fixes
• Addded an authoring impl class for authored structs / enums which don't need a wrapper to hold onto attribute information which is used as part of the WinRT type check
• Added support for out parameters
• Added tests to exercise these scenarios

Contributes to #309

[manodasanW]

You probably should disable whitespace diff when reviewing this PR.

[Scottj1s]

should this be moved to the Samples folder?

[manodasanW]

I probably want to rename this to be a test, this component is more for test purposes than to serve as a sample. I will address that in a future PR.

[Scottj1s]

    private static readonly Dictionary<string, MappedType> MappedCSharpTypes = new Dictionary<string, MappedType>()

Ideally, the 3 sources of mapping data would derived from a single source. Meantime, can we add comments to all 3 to indicate the other two need to be kept in sync?

CsWinRT/src/cswinrt/helpers.h

Line 450 in 1b4ff32

inline const std::initializer_list<mapped_type> get_mapped_types_in_namespace(std::string_view typeNamespace)

CsWinRT/src/WinRT.Runtime/Projections.cs

Line 25 in 1b4ff32

static Projections()

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Refers to: src/Authoring/WinRT.SourceGenerator/WinRTTypeWriter.cs:271 in e3f6fd1. [](commit_id = e3f6fd1, deletion_comment = False)

[Scottj1s]

exciting!