Creating convention for Azure templates based on directory structure

[BernieWhite]

PSDocs conventions are a feature added to PSDocs v0.8.0.

Conventions allow automatic naming of output documents.

Currently we have a manual sample (below) to name documents based on their directory structure.

# Generate a standard name of the markdown file. i.e. <name>_<version>.md
$template = Get-Item -Path $_.TemplateFile;
$templateName = $template.Directory.Parent.Name;
$version = $template.Directory.Name;
$docName = "$($templateName)_$version";

This can now be converted to a convention to avoid using extra code for common scenarios.