New Event uuid column and autoincremental id

Re added the autoincremental id column for the Event table, and added a
new column to store the event uuid. The uuid will be exposed to the user
as the id of the event, but internally the event will be handled using
the value of the id column.

Change-Id: I43464c6079bf7631fda0c4ab112b8f874c6190a3
Co-Authored-By: chmouel@enovance.com
Closes-Bug: #1261883
Merge "New Event uuid column and autoincremental id"