feature(xrk): add new env named Flozen Lake and DQN algorithm.

[rongkunxue]

Description

Add adaptation to gymnasium environment and give examples based on DQN algorithm

Related Issue

TODO

Check List

• merge the latest version source branch/repo, and resolve all the conflicts
• pass style check
• pass all the tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.89%. Comparing base (e28438c) to head (d41ece2).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #781      +/-   ##
==========================================
+ Coverage   75.87%   75.89%   +0.02%     
==========================================
  Files         679      681       +2     
  Lines       55249    55287      +38     
==========================================
+ Hits        41920    41962      +42     
+ Misses      13329    13325       -4     

Flag	Coverage Δ
unittests	75.89% <ø> (+0.02%)	⬆️

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