refactor(postfix): rework postscreen settings

This patch adjusts the postscreen settings regarding dnsbls and alike to
hopefully speed up the processing time of emails and make the place more
inviting for wanted e-mails.

images/postfix/.release

-release=0.2.3
+release=0.3.0

images/postfix/config/main.cf

@@ -89,21 +89,16 @@ virtual_transport = lmtp:inet:dovecot-internal:24
 
 postscreen_access_list = permit_mynetworks
 postscreen_blacklist_action = drop
-postscreen_greet_action = enforce
+postscreen_greet_action = ignore
 postscreen_dnsbl_action = enforce
 postscreen_dnsbl_threshold = 3
-postscreen_dnsbl_whitelist_threshold = -1
+postscreen_dnsbl_allowlist_threshold = -1
 postscreen_dnsbl_sites =
         zen.spamhaus.org*3,
         ix.dnsbl.manitu.net*3,
-        multi.uribl.com,
         bl.spamcop.net,
         b.barracudacentral.org,
-        dnsbl-1.uceprotect.net,
         safe.dnsbl.sorbs.net,
-        ubl.unsubscore.com,
-        psbl.surriel.com,
-        dnsbl.inps.de,
         swl.spamhaus.org*-10,
 
 ########
@@ -123,7 +118,6 @@ smtpd_recipient_restrictions =
         reject_unknown_recipient_domain,
         reject_invalid_hostname,
         warn_if_reject reject_unauth_pipelining,
-        permit_sasl_authenticated,
         permit_mynetworks,
         reject_unverified_recipient,
         reject_unauth_destination,