Confirmation messages for bookings

[hysinh]

As a Registered user, I can view a confirmation message so that I know that my booking has been created or updated correctly

• [ ] AC1 Given that I am a registered user, I will see a confirmation message if I create a new booking or an error message if the form is completed incorrectly.
• [ ] AC2 Given that I am a registered user, I will see a confirmation message if I update a current booking or an error message.