Checkmk Werk 15973: Remove deprecated host label "resource_group" for Azure Resource Group hosts

ID: 15973 Title: Remove deprecated host label "resource_group" for Azure Resource Group hosts Component: Checks & agents Level: 1 Class: New feature Version: 2.3.0b1 As announced in https://checkmk.com/werk/15261, the "resource_group" host label has been replaced with the label "cmk/azure/resource_group". Users referencing the old label have to switch to the new one since with this werk, the "resource_group" label will no longer be provided for Azure Resource Group hosts.