Hello Libvirt community

This is my first time working on a GSoC project with Libvirt. SaltStack is an open-source project that facilitates configuration management for IT infrastructures and Virt is a module of SaltStack.

The following 9 PRs summerizes the work I have done during this summer. The goal is to make existing Libvirt API domain properties configurable in Salt Virt in order to support advanced performance tuning.  5 PRs have been merged so far and another 4 are under reviewing. Although all basic unit tests have passed, I believe more rigorous tests are needed before using these features in production. I will spend more time later on adding more tests. 

Acknowledgements
===============
Sincere thanks to my mentors Cedric Bosdonnat (cbosdo), Pedro Algarvio
(s0undt3ch) and Tyler Jones (Akm0d) for their patient support and advice.

Thank Wayne Werner (waynew), Daniel Wozniak (dwoz) Megan Wilhite (ch3ll) from SaltStack community for being very responsive on my questions and code reviews.

and Libvirt organisation for providing this opportunity for me to learn and grow.

PRs
===============
CPU tuning and io threads allocation (reviewing)
https://github.com/saltstack/salt/pull/58196

Memory backing (reviewing)
https://github.com/saltstack/salt/pull/58167

CPU model, topology and NUMA node tuning (reviewing)
https://github.com/saltstack/salt/pull/57879

Memory tuning (reviewing)
https://github.com/saltstack/salt/pull/57636

Polish parameter doc (merged)
https://github.com/saltstack/salt/pull/57086

Map null to None in sls file (merged)
https://github.com/saltstack/salt/pull/57451

Firmware auto select (merged)
https://github.com/saltstack/salt/pull/57396

Boot VMs with UEFI (merged)
https://github.com/saltstack/salt/pull/56613

Boot parameter update fix (merged)
https://github.com/saltstack/salt/pull/56562

Kind regards,
Guoqing LI