Configure Schleuder lists to fetch keys from keys.openpgp.org
Originally created by @zen on #17528 (Redmine)
Schleuder lists hosted by us currently use the SKS Keyservers pool to fetch/renew keys periodically. To prevent signature flooding attacks, we need to switch the keyserver to “keys.openpgp.org”.
We can also use their Onion service to limit infoleaks.