feat(authn): add templatized error page

ref CNOUS/mse#3907

internal/proxy/director/layer/authn/options.go

@@ -2,6 +2,7 @@ package authn
 
 type Options struct {
 	TemplateDir string
+	Debug       bool
 }
 
 type OptionFunc func(*Options)
@@ -9,6 +10,7 @@ type OptionFunc func(*Options)
 func NewOptions(funcs ...OptionFunc) *Options {
 	opts := &Options{
 		TemplateDir: "./templates",
+		Debug:       false,
 	}
 
 	for _, fn := range funcs {
@@ -23,3 +25,9 @@ func WithTemplateDir(templateDir string) OptionFunc {
 		o.TemplateDir = templateDir
 	}
 }
+
+func WithDebug(debug bool) OptionFunc {
+	return func(o *Options) {
+		o.Debug = debug
+	}
+}