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/rules/rules_test.go

@@ -323,7 +323,7 @@ func TestDirectoryThatDoesNotExistStopsTheStart(t *testing.T) {
 
 	dir := filepath.Join(t.TempDir(), "rules.d")
 
-	wantRefused(t, dir, "SWW_WAF_RULES_DIR cannot be read: open "+dir+
+	wantRefused(t, dir, "SWW_WAF_RULE_FILES_DIR cannot be read: open "+dir+
 		": no such file or directory")
 }
 
@@ -352,7 +352,7 @@ func TestEmptyDirectoryLoadsNoRulesAndSaysSo(t *testing.T) {
 func TestRuleFilesOffReadNothing(t *testing.T) {
 	t.Parallel()
 
-	// SWW_WAF_RULES_DIR does not exist, which would stop the start.
+	// SWW_WAF_RULE_FILES_DIR does not exist, which would stop the start.
 	params, _ := newParams(filepath.Join(t.TempDir(), "rules.d"))
 	params.Enabled = false