Migrate Documentation to Markdown and External Help

[lipkau]

Description

In order to have a documentation that is easier to access, easier to edit and maintain, and more flexible, we shall use PlatyPS for the help of the function.
Discussion on this topic: AtlassianPS/AtlassianPS#1

Task

• Migrate all Comment Based Help to .md files in /docs

Import-Module MyAwesomeModule
New-MarkdownHelp -Module MyAwesomeModule -OutputFolder .\docs

• Edit the .md files (.EXAMPLE block can have more that 1 command in it)
• Create the about_<module>

New-MarkdownAboutHelp -OutputFolder C:\Test -AboutName

• Make AppVeyor generate the ExternalHelp file (.xml) when building

New-ExternalHelp -Path ".\docs" -OutputPath "out\platyPS\en-US"

• Remove the Comment Based Help from all functions in the module