games/acm: Deprecate.

The port is not maintained, abandoned upstream and it does not work with any of
the instructions found online:

https://www.icosaedro.it/acm/manual/acmdoc-basic.htm
https://www.gnu.org/software/acm/manual/acm.html#Launching-a-game

In addition the distribution is hosted by amdmi3@ who was not aware of that.

PR: 257223
Reported by: dufresnep@zoho.com