Add man pages to the games

Based on how the extrautils apps implement it.

I would like to work on this.

I am following the example of cur.rs from extrautils.

• baduk
• commie
• dem
• flappy
• h4xx3r
• ice
• minesweeper
• reblox
• redoku
• rusthello
• snake

I forgot to mention: to test this you can make a standard Redox build with your changes. The cookbook scripts automagically run the manpage generator during the staging step of the packages. It works by scanning through the sources and picking up everything it finds between @MANSTART{appname} and @MANEND.

mentioned in merge request !33