Switch Inventory Query to Knife Search

What

This merge request changes the way we query Chef for the Gitaly inventory list. Instead of using knife ssh, which becomes very slow for large inventories, we now use knife search for more efficient queries.

Because the SSH-based approach allowed us to check node uptime for exemptions, we are now moving the uptime-based exemption logic into the playbook itself.

Why

This change reduces the time and overhead associated with querying large chef for large inventories via SSH and avoids unnecessary calls to Chef. It improves performance and reliability when working with many nodes.