Agree on a process to store information about and ping past PayPal donors

Quite some people send us money via PayPal, and as a result we have a list of email addresses. Shall we use this list for targeted communication, e.g. sending them a yearly email suggesting to donate again? This could be done at the same time as we’re doing a fundraising campaign announced on our website, that explains what are our plans for next year (or so).

Implementation-wise (that’s not exactly what this ticket about, but details may matter to make a decision here):

• one should probably make sure to not spam people who have set up a recurring donation;
• IMO the first time we send this email, we should make it clear that it’s a one-time thing, and propose people to opt-in for receiving similar messages in the future; and then we need to keep track of who has not opted-in to avoid spamming them again, while still being able to email new donors.

• Where should we store these lists? Is the fundraising repo, ok?
• We should be able to track who we wrote already and not bother people more than necessary.
• We should allow people to opt-out.

Parent Task: #9855 (closed)

Original created by @intrigeri on 9529 (Redmine)