Cakephp 5 (+ php 8.4, phpunit 11)

[didoda]

This updates dependencies and codebase to use cakephp 5.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (5174c25) to head (0f8d748).
Report is 14 commits behind head on master.

Additional details and impacted files

@@              Coverage Diff              @@
##             master     #1209      +/-   ##
=============================================
+ Coverage     99.66%   100.00%   +0.33%     
- Complexity     1351      1352       +1     
=============================================
  Files            98        97       -1     
  Lines          5327      5317      -10     
=============================================
+ Hits           5309      5317       +8     
+ Misses           18         0      -18     

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