gnugo: add page (#22197)

Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>
Co-authored-by: Wiktor Perskawiec <wiktor@perskawiec.cc>
Co-authored-by: Ivan Baluta <ivanbaluta.dev@gmail.com>

pages/common/gnugo.md

@@ -0,0 +1,24 @@
+# gnugo
+
+> Play Go on the command-line.
+> More information: <https://www.gnu.org/software/gnugo/gnugo_3.html>.
+
+- Start an interactive Go game:
+
+`gnugo`
+
+- [Interactive] Place a stone at row 5 and column J once in game:
+
+`J5`
+
+- Start a game with 5 handicap stones with opponent of level 5:
+
+`gnugo --handicap 5 --level 5`
+
+- Resume a game from a specific file at move 123:
+
+`gnugo {{[-l|--infile]}} {{path/to/game.sgf}} {{[-L|--until]}} 123`
+
+- Give a rough score estimate of a position:
+
+`gnugo --score estimate {{[-l|--infile]}} {{path/to/game.sgf}}`