backport selinux fixes and use faster runners #291

Job	Run time
image (x86_64, base/base-disk)	4m 59s
image (aarch64, base/base-disk)	5m 0s
live-iso (x86_64, flagship/flagship-live)	4m 57s
live-iso (x86_64, gnome/gnome-live)	4m 59s
live-iso (x86_64, kde/kde-live)	4m 53s
live-iso (x86_64, pantheon/pantheon-live)	5m 0s
live-iso (aarch64, flagship/flagship-live)	4m 19s
live-iso (aarch64, gnome/gnome-live)	4m 51s
live-iso (aarch64, kde/kde-live)	4m 52s
live-iso (aarch64, pantheon/pantheon-live)	4m 16s
push-image	1s
	48m 7s

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