Rename the settings whose names do not say what they control (closes #234)

Applies the setting renames of the naming audit under the SWW_WAF_ and
SWW_RPROXY_ prefixes, with sneak's names for the IP reputation cache
time and the two time limits, which now take milliseconds. The rproxy
log field default_disposition becomes waf_backend_no_answer, and
config.Config and config.FromEnvironment become config.WAF and
config.WAFFromEnvironment. Go fields, test names and prose follow. No
aliases; nothing reads the old names.

Model: opus-5-5

internal/reputation/dnsbl.go

@@ -60,8 +60,8 @@ type DNSBLParams struct {
 	// host's, as /etc/resolv.conf names it.
 	Resolver netip.AddrPort
 	// CacheTTL is how long a verdict is used after it was fetched
-	// (SWW_WAF_REPUTATION_CACHE_TTL), and Timeout how long a query may take
-	// (SWW_WAF_REPUTATION_TIMEOUT).
+	// (SWW_WAF_IP_REPUTATION_CACHE_TTL), and Timeout how long a query may
+	// take (SWW_WAF_DNSBL_ABUSEIPDB_TIMEOUT_MS).
 	CacheTTL time.Duration
 	Timeout  time.Duration
 	// Now tells the time, normally time.Now in UTC.