ci: Add PMD and CPD checks to Maven build workflow

[RoiSoleil]

Adds PMD and CPD static analysis checks to the GitHub Actions maven.yml workflow and updates the README to display the workflow badge.

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PR created automatically by Jules for task 1276871137883998607 started by @RoiSoleil

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.56%. Comparing base (54a3553) to head (19ee639).
⚠️ Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #266   +/-   ##
=========================================
  Coverage     73.56%   73.56%           
+ Complexity     3258     3257    -1     
=========================================
  Files           422      422           
  Lines         14547    14547           
  Branches       1271     1271           
=========================================
  Hits          10701    10701           
  Misses         3306     3306           
  Partials        540      540           

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