Allow the ability to disable file attachments in emails per-request, maybe per-user

Our HR staff prefer the email notifications to not include the file attachments that the user submits or they submit.

They also suggested that if the submitters could have it as a setting in their notifications for them to turn on their preference, as well as already sent attachments not being included.
(Ex: submitter uploads a certificate and receipt which doesn't get sent via email at all, but HR attaches a form for them to sign and the user gets only the form as an attachment back).