Add possibility to do a rolling apps update (extend ZDU functionality)

Problem Definition

Apps downtime during the app upgrade process in Jira Server DC ends with users not being able to use the app.

Suggested Solution

As a Jira DC admin I would like plugins/apps/applications updates to be triggered sequentially and not in parallel on my DC nodes.

The node which is currently performing the plugins/apps/applications update should be switched to MAINTENANCE mode (/status endpoint) so users are never affected by plugins/apps/applications updates.

The described above functionality might extend the existing Zero Downtime Upgrades (ZDU) functionality in Jira Data Center.

More on Zero Downtime Upgrades: https://confluence.atlassian.com/adminjiraserver/upgrading-jira-data-center-with-zero-downtime-938846953.html