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/abuseipdb.go

@@ -65,8 +65,8 @@ type AbuseIPDBParams struct {
 	MinScore    int64
 	DailyBudget int
 	// CacheTTL is how long a score is used after it was fetched
-	// (SWW_WAF_REPUTATION_CACHE_TTL), and Timeout how long a check may take
-	// (SWW_WAF_REPUTATION_TIMEOUT).
+	// (SWW_WAF_IP_REPUTATION_CACHE_TTL), and Timeout how long a check may
+	// take (SWW_WAF_DNSBL_ABUSEIPDB_TIMEOUT_MS).
 	CacheTTL time.Duration
 	Timeout  time.Duration
 	// Now tells the time, normally time.Now in UTC.