Change the status names to be more descriptive

To a new user, the statuses such as "Idle" and "Do not disturb" may be confusing.

I suggest we change them to "Away" and "Busy" because they give more information.

Idle suggests that someone is just not sending messages but able to see them, but most of the time they're AFK, and will not see the message.

Do not disturb could be telling someone to not message another person, but really it means they're not receiving notifications.