[Shogi] Add Game class

[sotetsuk]

#1127

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.98%. Comparing base (d6670da) to head (9f96f0d).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pgx/_src/games/shogi.py	77.77%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1271   +/-   ##
=======================================
  Coverage   79.98%   79.98%           
=======================================
  Files          62       62           
  Lines        5771     5781   +10     
=======================================
+ Hits         4616     4624    +8     
- Misses       1155     1157    +2     

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