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/config/viper_test.go

@@ -11,7 +11,7 @@ import (
 func TestTokenSetEmptyInTheEnvironmentStopsTheStart(t *testing.T) {
 	t.Setenv(adminToken, "")
 
-	_, err := config.FromEnvironment(config.NewViper())
+	_, err := config.WAFFromEnvironment(config.NewViper())
 
 	want := adminToken + ": is shorter than 32 characters"
 	if err == nil || err.Error() != want {