BookingId mandatory for Messages

[osarrat]

While implementing the full API booking flow, we found out hard and counter-intuitive to leave open the sending of messages WITHOUT a Booking context.
As a consequence, we propose to :

1. force to have all messages attached to Booking context (bookingId required in POST /messages) ;
2. enable the sending of messages while creating a Booking (message optional attribute added in POST /bookings as it is already available in the PATCH /bookings endpoint) ;
3. add an INITIATED bookingStatus (this bookingStatus is just used in the full API booking flow) to differenciate booking started just a casual chat and a formal booking request made by the passenger to the driver.

[adelcasse]

Approved