sagemathgh-37810: build/pkgs/gambit: Remove

    
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Removing this broken experimental package, as proposed in 2020.
- Closes sagemath#30156

Also removing the module providing outdated "standalone instructions" to
use Gambit.

Keeping the various references to Gambit tagged with `# optional -
gambit`. This will be updated in the follow-up PR"
- sagemath#37809


The motivation for opening this PR to remove `gambit` now (2024) is that
it removes a remaining use of the function `sdh_setup_bdist_wheel` (the
old gambit Python package could not be installed using pip). This a step
for the modernization of the build frontend for Python packages in the
Sage distribution:
- sagemath#35618

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- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

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URL: sagemath#37810
Reported by: Matthias Köppe
Reviewer(s): John H. Palmieri

src/doc/en/reference/game_theory/index.rst

@@ -8,7 +8,6 @@ Game Theory
    sage/game_theory/matching_game
    sage/game_theory/normal_form_game
    sage/game_theory/catalog_normal_form_games
-   sage/game_theory/gambit_docs
    sage/game_theory/parser
 
 .. include:: ../footer.txt

src/sage/game_theory/normal_form_game.py

@@ -236,8 +236,7 @@
   `Gambit <http://gambit.sourceforge.net/>`_ [Gambit]_. At present this is
   the only gambit algorithm available in sage but further development will
   hope to implement more algorithms
-  (in particular for games with more than 2 players). To install it,
-  type ``sage -i gambit`` in the shell.
+  (in particular for games with more than 2 players).
 
 * ``'enumeration'``: Support enumeration for 2 player games. This
   algorithm is hard coded in Sage and checks through all potential