Add opt-in/opt-out email messaging support (e.g. newsletters and announcements)

[brndd]

Most organizations, including Tampere Hacklab, want to be able to send e-mails to all members. Examples:

• Invitations to official association assemblies
• Announcements concerning all members
• Regular newsletters

To support this, the system should have several different categories of emails that users can opt in or out of, and the mass email sending UI needs an option to select a category the email is under (e.g. announcement, newsletter), which decides which users it is sent to.

[tswfi]

related (if not even duplicate) #265

[olmari]

I was about to say same that @tswfi that this is at very least same but even more elaborate (not necessarily bad thing).

Of course another take is that should this be "just" an N+1 mailinlist "subcribe-automation" or even backend means to create the mail in Mulysa... But the very core feat is indeed at least singular "subsctibe to mailinglist"..

At very old not-mulysa this was practically done so that system itself sent subscribe mail to defined mailing list subscribe address, which can work when mail server is specifically set so allow that.

So I suppose now you got your MVP and the Stretch Goal defined for this, in reverse order :D

[brndd]

The difference between this and #265 is that a mailing list is an external service (e.g. on Freelists) that usually everyone can send emails to, whereas this is for mails sent directly by Mulysa.