[2203312] VM list takes long time to load when there are 1K VMs and more

Description of problem: When 1000 or more VMs are created on a cluster, the VM list appears with a significant delay, despite that all VMs are stopped.

Version-Release number of selected component (if applicable):

How reproducible: always

Steps to Reproduce:
1. Create 1000 or more VMs on a cluster
2. Open Virtualization VirtualMachines page
3.

Actual results: VM list is loaded after delay

Expected results: VM list is loaded instantly.

Additional info:
The vCPU usage is high, may be related to these bugs: https://bugzilla.redhat.com/show_bug.cgi?id=2025525
https://bugzilla.redhat.com/show_bug.cgi?id=1946232