ci: update ci with reusable workflows and new release flow

[k4black]

Description

Update CI to use reusable workflows and configs from .github repo

[codecov]

Codecov Report

Attention: 146 lines in your changes are missing coverage. Please review.

Comparison is base (6389346) 36.94% compared to head (12b3ddc) 45.53%.
Report is 27 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #61      +/-   ##
==========================================
+ Coverage   36.94%   45.53%   +8.59%     
==========================================
  Files          24       25       +1     
  Lines        1903     2106     +203     
==========================================
+ Hits          703      959     +256     
+ Misses       1200     1147      -53     

Flag	Coverage Δ
unittests	45.53% <60.64%> (+8.59%)	⬆️

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Files	Coverage Δ
checker/actions/contributing.py	0.00% <ø> (ø)
checker/course/__init__.py	100.00% <100.00%> (ø)
checker/course/config.py	100.00% <100.00%> (ø)
checker/course/schedule.py	78.78% <100.00%> (+4.17%)	⬆️
checker/exceptions.py	97.67% <100.00%> (ø)
checker/executors/__init__.py	100.00% <100.00%> (ø)
checker/executors/sandbox.py	87.77% <ø> (ø)
checker/testers/__init__.py	100.00% <100.00%> (ø)
checker/testers/cpp.py	93.40% <100.00%> (-0.15%)	⬇️
checker/utils/__init__.py	100.00% <100.00%> (ø)
... and 13 more

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