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/waf/trappaths_test.go

@@ -25,10 +25,10 @@ func TestTrapPathBansAsABanRuleDoes(t *testing.T) {
 
 	// A block rule for the same path: the trap path comes first.
 	s, clk, server := startWithClock(t, "", map[string]string{
-		trapPaths:   trapPathList,
-		rulesDir:    writeRules(t, `wp  path  block  ^/wp-login\.php$`),
-		allowNets:   allowed,
-		banResponse: "429",
+		trapPaths:    trapPathList,
+		ruleFilesDir: writeRules(t, `wp  path  block  ^/wp-login\.php$`),
+		allowNets:    allowed,
+		banResponse:  "429",
 	})
 	start := clk.Now()
 
@@ -153,8 +153,8 @@ func TestTrapPathsNeedNoRuleFiles(t *testing.T) {
 	t.Parallel()
 
 	s, _, _ := startWithClock(t, "", map[string]string{
-		trapPaths:               trapPathList,
-		"SWW_WAF_RULES_ENABLED": "false",
+		trapPaths:                    trapPathList,
+		"SWW_WAF_RULE_FILES_ENABLED": "false",
 	})
 
 	s.request(client, "/xmlrpc.php", http.StatusForbidden,