Mailing list and newsletter use case no more covered by the Mail API

With IterableMimeMessageFactory, there is two use case to be covered:

1. multiple different mails are created from a template (ie: SecureTemplateMimeMessageFactory)
2. the same message is sent to multiple recipients (ie: MessageMimeMessageFactory)

In the first case, all message SHOULD and will have a different `Message-ID` headers, but in the second case, all message MUST have the exact same `Message-ID` headers, since this is the exact same message being sent. This the use case of the mailing list, where a user should be able to reply to message sent by the list, and reference that message for all other subscribers properly.

Since XWIKI-12128, we use the `Message-ID` for tracking mail sending, and XWIKI-12140 cause message from MessageMimeMessageFactory to have different `Message-ID`. Both of them should be somehow reverted.