feat: add stdout and filesystem notification channels (#2925)

* feat: add filesystem and stdout notification channels

* configure through env vars

* compile

* feat: add compact option for debug notification channels

* fix channel mock generation

* avoid sensitive information in error message

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

* add review improvements

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

internal/notification/senders/email.go

@@ -0,0 +1,25 @@
+package senders
+
+import (
+	"github.com/caos/zitadel/internal/config/systemdefaults"
+	"github.com/caos/zitadel/internal/notification/channels"
+	"github.com/caos/zitadel/internal/notification/channels/smtp"
+)
+
+func EmailChannels(config systemdefaults.Notifications) (channels.NotificationChannel, error) {
+
+	debug, err := debugChannels(config)
+	if err != nil {
+		return nil, err
+	}
+
+	if !config.DebugMode {
+		p, err := smtp.InitSMTPChannel(config.Providers.Email)
+		if err != nil {
+			return nil, err
+		}
+		return chainChannels(debug, p), nil
+	}
+
+	return debug, nil
+}