Use en_US.UTF-8 as default for LANG, which is what previously was
used and is also needed to properly work on non-us/latin setups[1].
In the customization tests, use a different value than the default
one to check that the customization does in fact work.
[1] http://git.app.eng.bos.redhat.com/git/spin-kickstarts.git/tree/rhel8/rhel-8.2-kvm-x86_64.ks#n4
Co-authored-by: Achilleas Koutsou <achilleas@koutsou.net>
The image definition is shared with the latest RHEL 8.y one (8.4 currently).
I expect that we the introduction of 8.5 support, we point the centos 8
distro at it.
The test repositories and manifests use the official CentOS composes. From
what I can tell, they are persistent. This is not guaranteed though, so we
might need to switch to RPMRepo at some point.
The "classic" CentOS 8 should also be buildable but due to the chicken and egg
issue (this commit will get into Centos "8.4" but Centos "8.4" isn't a thing
yet), we cannot test it and therefore it might be broken.
Signed-off-by: Ondřej Budai <ondrej@budai.cz>
