Add s390x support and tweak some virtio devices

[bcl]

[coveralls]

Pull Request Test Coverage Report for Build 9473274712

Details

• 0 of 6 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.009%) to 43.483%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/pylorax/installer.py	0	6	0.0%
<!--	Total:	0	6	0.0%	-->

Totals
Change from base Build 9387788059:	-0.009%
Covered Lines:	1614
Relevant Lines:	3502

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💛 - Coveralls

[bcl]

Unit tests actually passed, just didn't get added here -- possibly due to github action issues yesterday.