Import upstream v0.16.25, stripped

Upstream commit: 3f657330c0f49a015a3a372fb59669b5cccbca6d
Enterprise-only files removed or emptied: 63
Enterprise-only snippets removed: 118 in 50 files
Dangling module declarations removed: 5
Edits turning enterprise off: 25
Third-party code: 14 files, 0 not in THIRD-PARTY.md
Renamed identifiers: 67 in 19 files
Verification: clean

The same Enterprise footprint as v0.16.24. The build check is clean
apart from the expected errors in the rebuilt-feature tests. A
bug-fix release: DKIM rotation, IMAP failed-login answers, DNSBL
multi-code scoring and negative TTLs, Pyzor on short messages, queue
quotas with an empty match, RocksDB info-log rotation, and
Autodiscover schema handling.

crates/common/src/lib.rs

@@ -194,7 +194,7 @@ pub struct Caches {
     pub dns_ipv6: CacheWithTtl<Box<str>, RecordSet<Ipv6Addr>>,
     pub dns_tlsa: CacheWithTtl<Box<str>, Arc<Tlsa>>,
     pub dns_mta_sts: CacheWithTtl<Box<str>, Arc<Policy>>,
-    pub dns_rbl: CacheWithTtl<Box<str>, Option<Arc<IpResolver>>>,
+    pub dns_rbl: CacheWithTtl<Box<str>, Option<Arc<[IpResolver]>>>,
 
     pub negative_cache_ttl: Duration,
 }