Support Ubuntu 20.04 and 22.04 mgmt and kvm template

[yadvr]

Add packer-based image builds for building Ubuntu 20.04 and 22.04 kvm/mgmt server template.

[ravening]

Add packer-based image builds for building Ubuntu 20.04 kvm/mgmt server template.

@rhtyd any idea when will ubuntu will be supported for mgt servers?

[yadvr]

I hope soon @ravening - it's a matter of a few hours to build a new template and test it. I can do one manually or write docs on how to create a template if you want to volunteer. (packer template would be great but would take some time to figure out)