games/freeciv21: New port: Freeciv for the 21st century

Freeciv21 takes its roots in the well-known FOSS game Freeciv
(games/freeciv) and extends it for more fun, with a revived focus on
competitive multiplayer environments. Players can choose from over 500
nations and can play against the computer or other people in an active
online community.

PR: 276244