Adapting i18n and add Simplified Chinese for web pages on branch 2.5.x

[inRemark]

Adapting i18n and add Simplified Chinese for web pages on branch 2.5.x.

Follow code style;
Only change the front-end code;
If the commit is approved, I will push a commit for the master branch.

Changes:

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (2.5.x@cdcce70). Click here to learn what that means.
Report is 1 commits behind head on 2.5.x.

Additional details and impacted files

@@           Coverage Diff            @@
##             2.5.x   #10607   +/-   ##
========================================
  Coverage         ?   38.76%           
  Complexity       ?    11920           
========================================
  Files            ?     3538           
  Lines            ?    94258           
  Branches         ?    10504           
========================================
  Hits             ?    36539           
  Misses           ?    54548           
  Partials         ?     3171           

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