Make instance restart function capable of restarting the cluster

[swicken-dotcms]

Is your feature request related to a problem? Please describe.
We added the ability to restart instances to dotCMS, however it only restarts the node you are connected to

Ticket: https://dotcms.zendesk.com/agent/tickets/107796

Describe the solution you'd like
Give an additional option to restart the entire cluster

Describe alternatives you've considered
After restarting the node you are connected to, you could refresh and get to a new node and hit restart on that as well, but with a lot of nodes this could be inconsistent.

HOW THE DOTCMS CLUSTER RESTART WORKS

Here's an example based on a two-node dotCMS Cluster:

-> FROM THE MAINTENANCE PORTLET:

1. Set up a working dotCMS Cluster. For Docker, please refer to: https://github.com/dotCMS/core/tree/master/docker/docker-compose-examples/cluster-mode
2. Once you made sure you can log into both nodes, go to the Settings > Maintenance > Tool portlet in any of them and scroll down to the bottom all the way to the Shutdown dotCMS section.
3. Check both I agree with the above and Shutdown dotCMS Cluster boxes.
4. The Rolling Delay in Seconds field will show up. For testing purposes, enter a lower value for it, for instance, 10. As you can see in the UI, this field allows you to set the number of seconds between each node in the cluster restarting.
5. Keep an eye on the log file from both nodes. Finally, click SHUTDOWN DOTCMS.
6. The node you're currently logged in will shut down immediately. The other node will restart after the specified amount of seconds. You can confirm the expected timing of the operation by checking the logs.

-> VIA THE REST ENDPOINT:

Using Postman, create a DELETE request with Basic Auth for the following Endpoint: http://localhost:8080/api/v1/maintenance/_shutdownCluster?rollingDelay=10 . The expected outcome must be the same as in the previous section -- i.e., shutting down the current node immediately , and the second node going down after 10 secs.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jcastro-dotcms]

The ticket's description has been updated with an explanation on how the cluster restart process can be achieved via the dotCMS back-end, and the REST Endpoint.

[bryanboza]

Fixed, tested on the QA server and now we are able to restart the entire cluster without problems.

Tested with the last master // Docker