hlsteam - new attempt at hashlink steam middleware library

Hi,

This is an updated version of my original submission a year ago [1].
I'm keeping it shorter this time - this does the same as the recently
committed libcsteamworks [2] for hashlink. This replaces the stub
library that is part of steamworks-nosteam. Net benefit is improved
support and maintainability of keeping the following indie games
runnable on OpenBSD: Dead Cells, Northgard, Dice Tribes: Ambitions,
Nuclear Blaze, Evoland Legendary Edition, Voidrun, possibly future
titles.

ok to import?

[1] https://marc.info/?l=openbsd-ports&m=163554939711525&w=2
[2] https://marc.info/?l=openbsd-ports&m=166753024405818&w=2