tests: fix unsubscription test (#12543)
prefix unsubscription link with url read from settings (#12543)
tests: add proper unquoting of signature
tests: don't recompute unsubscribe link signature (#12806)
don't show identifier's scheme on unsubscription page (#12544)
unsubscribe link (#10795)
announces send command (#10805)
Ran as cron job every 5 minutes
api: subscriptions management endpoint (#10794)
api: newsletters retrieval endpoint (#10794)