Change New-MarkdownCommandHelp dramatically.

[JamesWTruher]

PR Summary

• Removed optional alpha sorting for parameters, this is always the case.
• Change to use fulltypes for parameters by default.
• Change to accept CommandInfo and PSModuleInfo objects.
• A transform attribute will convert strings to objects rather than the transformer.
• Add some overloads to the transformer to take those objects.
• Files are grouped by module name, and placed in their own directory.
  • If they're not associated with a module (like a script), then they go into the 'outputfolder'.
• Fix a bug in the markdown reader to include the first input or output if it doesn't have a description.
• Added a bunch of tests for new-markdowncommandhelp.

PR Context