Install kio_version.h in the KIO include prefix
See https://mail.kde.org/pipermail/kde-frameworks-devel/2022-January/120608.html for the background on this.
This is considered compatible as both prefixes are included in the build metadata, and local tests with Plasma and PIM confirm that so far.
I picked KIO as a test subject as kio_version.h is one of the most widely used version headers. I'd suggest we try this here for 5.91 and if that doesn't cause any fallout roll this out to all frameworks.