Related to task #3632, we will change the "notification by role" personal setup that seems unused, probably because half of the options are without effect (only reports about this feature is just from people that unchecked everything and still received notifs) and another half very useless (hum, a checkbox to allow someone not to receive notification when he is added by someone else in CC? it is really necessary to bother making a difference whether an update is a file attachement with our without a comment?).

task #3632 implies to add in CC people that post comments, etc. This will allows users to on an item basis stop notifications if they are no logged in interested.

In this spirit, it only makes sense to propose three options:
- boolean about receiving mail for the update done by ourselve (someone may like to get notifs as confirmation, someone may not want to get mail from his own actions)
- boleean to receive mail only on item closing, useful for people just wanting to know when bug get closed, without really discussing on the item, without caring about developers chats.
- boolean to receive mail only on item status change, same reasons as the previous