* feat(ci): Introduce a stable tag
The "stable" and "latest" tags are equivalent. Given "testing" and "unstable"
tags are used, users may likewise figure that the current stable release uses
the "stable" tag
* chore(image-info): Use stable tag
This will rebase to stable on freshly installed images
* chore(os-branch-select): Support stable tag
* chore(readme): Use :stable instead of :latest
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Co-authored-by: Kyle Gospodnetich <me@kylegospodneti.ch>
