Can we have config for notification count / limit for number of visible notifications?

[Shajansheriff]

I have a use-case to show only one latest notification through out my application lifetime. Right now we have options to clear all the notifications before showing the new notification.
this.notifications.clearAll().success('message')

Even with autoclear config, we have to call clearAll to be safe to show one at a time.

so I suggest to have globals/config 'ember-cli-notifications: { 'count': 1 }, this will limit to one latest notification.

[Shajansheriff]

Instead of the above suggestion, can we add a config to prevent adding duplicate notification message? @mansona