Automatically detect templates in a scan path

[BernieWhite]

With PSDocs v0.9.0 we can scan a sub-directory and generate documentation for templates based on a schema with selectors.

Instead of integration code like this:

# Scan for Azure template file recursively in the templates/ directory
Get-AzDocTemplateFile -Path templates/ | ForEach-Object {
    # 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";

    # Generate markdown
    Invoke-PSDocument -Module PSDocs.Azure -OutputPath out/docs/ -InputObject $template.FullName -InstanceName $docName;
}

or

Get-AzDocTemplateFile -Path templates/ | ForEach-Object {
    Invoke-PSDocument -Module PSDocs.Azure -OutputPath out/docs/ -InputObject $_.TemplateFile -Convention 'Azure.NameByParentPath';
}

we want this:

Invoke-PSDocument -Module PSDocs.Azure -InputPath . -Convention 'Azure.NameByParentPath' -OutputPath 'out/docs/'