CentOs End of Life?

[Stephen Hemminger]

While reworking tap device, one issue is how to keep (or drop) the support
of older Enterprise releases. The tap flow support is doing some workarounds
to include missing support, but these are not the right way to do it.

The question is: is this even worth keeping?
CentOS 7 reaches end of life in June 2024.
CentOS 7 is using a kernel which is no longer supported.

If we drop CentOS 7, that means dropping RHEL7 and would need to be hightlighted
in the docs.