Send-EmailMessage: More Flexible Attachments and Linked Resources

[Viajaz]

The ability to have more flexible attachments (other than just specifying path) would be useful.

The easiest way to do this is to change the $Attachment Parameter to [object[]] type and rely on MimeKit.AttachmentCollection.Add() which supports both Strings and MimeEntity

Although this doesn't really help with LinkedResources for things like changing changing attachment meta-data, such as Content-Disposition and Content-Id which is required for inline images in HTML emails in some emails. Perhaps LinkedResources can be exposed as a parameter too? Could be a number of ways to implement this as a more polished easy-to-use solution, maybe a separate -InlineAttachments Parameter that handles both?

https://www.mimekit.net/docs/html/Creating-Messages.htm#UsingBodyBuilder

[Viajaz]

Quick and dirty idea if one doesn't want to deal with MimeUtils.GenerateMessageId handling

if ($InlineAttachments) {
	foreach ($A in $InlineAttachments) {
		$LR = $BodyBuilder.LinkedResources.Add($A)
		$LR.ContentId = Split-Path -Path $A -Leaf
	}
}

[PrzemyslawKlys]

Care for a PR? Having inlineattachments is required, especially if I want to support the same thing as PSWriteHTML module have for sending emails.