email: change newsletter link that wouldn't affect our spam score

[maximbaz]

The "sign up to our newsletter" link in the membership email adds +1.5 to our spam score (URIBL_GREY(1.50)[eepurl.com:url]).

Tilmeld dig vores nyhedsbrev [http://eepurl.com/hZhf_D], hvor vi årligt sender...

We don't include this in the donation receipt email, so that mail is not affected.

Ideally we should link to our own domain (e.g. https://giveffektivt.dk/tilmeld-nyhedsbrev) which would not be greylisted, and this link can simply HTP 307 redirect to url of whatever mailing list provider we want people to use.

[lindeloev]

Good idea. I'll create a page in a few days and post the link here. The current mail-list signup is acting up on mobile.