Changes

tsk78 Adds to the admin's private view the list of all events ordered by
creation date
Adds a new view with a datatable for the list of all events and buttons
for manage them Modifies Event entity adding the create date Modifies
the database with the create date column (createdAt) Modifies the event
datasets adding the create date column Adds the util class
AdminRoleCaller to execute tests as admin