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/messages/sms.go

@@ -0,0 +1,15 @@
+package messages
+
+import "github.com/caos/zitadel/internal/notification/channels"
+
+var _ channels.Message = (*SMS)(nil)
+
+type SMS struct {
+	SenderPhoneNumber    string
+	RecipientPhoneNumber string
+	Content              string
+}
+
+func (msg *SMS) GetContent() string {
+	return msg.Content
+}