Suggested bookings to be attached to the event

[jbenito]

[By DMC, in CC]

I am one of the managers of an Indico meeting. Today I received a mail
with a confirmation that the meeting will be recorded (this was
requested by another manager).
In the recording page there is a message saying "Please make sure that
you have booked the room". Just in case, I go to check it to the
"booking" section of the event, but nothing appears there. Knowing how
Indico works, I go to the Room Booking module and find the booking there.
It would be nice that if a booking is created before an event, in the
"booking" section of the event there is a button that allows you to
associate an existing booking to your event. The button could even show
a list of bookings in the same room as the event and at similar times.
This could even be proposed automatically in the "booking" section ("We
noticed that there is a booking in the same room and the same time
created by XYZ, do you want to associate the booking to your event"?

[jbenito]

duplicated: see #777