docs: hvsupport: Add support for deprecating hypervisor implementations

docs: hvsupport: Add support for deprecating hypervisor implementations

Allow expressing that a hypervisor implementation was deleted by adding
a end-version when the implementation was removed to our hypervisor
support matrix.

This patch hacks the perl script that generates the support matrix to
support comments like:

.domainQemuAttach = qemuDomainQemuAttach, /* 0.8.3 (deprecated: 5.5.0) */

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>