Add function to send a notification mail

pkg/notifications/mail.go

@@ -16,6 +16,8 @@
 
 package notifications
 
+import "code.vikunja.io/api/pkg/mail"
+
 type Mail struct {
 	from       string
 	to         string
@@ -69,3 +71,14 @@ func (m *Mail) Line(line string) *Mail {
 
 	return m
 }
+
+func SendMail(m *Mail) error {
+	opts, err := RenderMail(m)
+	if err != nil {
+		return err
+	}
+
+	mail.SendMail(opts)
+
+	return nil
+}