Add standardized help schema for enums, classes, DSC Resources, and interfaces

[michaeltlombardi]

As an engineer writing and maintaining DSC Resources using enums and classes, I want to be able to document my enums and classes in a standard and supported way to reduce my cognitive load and custom implementation needs.

Right now, documenting enums and classes is either a manual process in an about topic or kludging together an arbitrary wrapper cmdlet like Get-MyEnum (to return one or more valid enums of a type) which can be documented.

With enums and classes forming the foundation of all DSC Resources in v3 forward, we need to have their documentation as well-supported as cmdlets; undocumented code borders on unusable code. The DSC Community has implemented a workaround solution but it relies on very specific structure and layout and is not part of the core language features and is specific to the organization's needs (though generally useful to other folks as well).

Proposal

I propose that at a minimum there be a defined standard for comment-based help and markdown schema for enums, classes, and DSC Resources (which may have slightly different documentation needs than normal classes) and one or more helper cmdlets for exporting the comment-based help to markdown.

If #83 is implemented, interfaces will also need to be documentable.