Add feature to prevent email notification when disabling user

Issue Summary

This is reproducible on Data Center: Yes

Steps to Reproduce

1. Disable any user 
2. The user will receive an email notification stating that their user was disabled

Expected Results

Being able to enable an option to prevent notifications.

Actual Results

The user will receive an email notification stating that their user was disabled

Workaround

There is no workaround for this. However, your team's email admins may be able to filter out the emails before they reach your customer's inboxes:

• Email titles: "Your Atlassian account has been deactivated", "Your Atlassian account will be permanently deleted"
• Email senders: noreply+<letters and numbers>@am.atlassian.com >> Change the Email domain to the correct one.