Issue Summary

The system property -Datlassian.pats.expiry.warning.days currently only supports a single integer value. The default warning period is 5 days before a token expires. The property can be set by system administrators to a single custom value that changes when the "expires soon" email notification is sent.

There should be an option to inform users multiple times about the expiry of their personal access tokens (for example 14, 7 and 2 days before the expiring of the tokens)