[new] bgp-perf

Simple port of the OpenBGPD performance test suite. It is early days
and doesn't have a formal release yet, but it would be handy to have
available as a port. Claudio is ok with it, I'm showing it here in case
anyone has nits/tweaks.

Information for inst:bgp-perf-0.0pl20251230

Comment:
OpenBGPD performance test suite

Description:
The OpenBGPD performance test suite contains two applications for
performance measurements.

The bgp-blaster tool can load mrtdump files into a table and emulate
many peers using that table.

The bgp-canary tool sends special UPDATE messages to the system under
test and measures the latency through the system. The statistics for
these measurements are available as an openmetric file.

Maintainer: The OpenBSD ports mailing-list <ports@openbsd.org>

WWW: https://github.com/openbgpd-portable/bgp-perf