docs: Migrate from npm to yarn and relax web dependencies

[vdusek]

• Migrate from npm to yarn for consistency.
• Same setup as in Crawlee.
• All 3 Python documentation projects (crawlee-python, apify-sdk-python, apify-client-python) now use an identical yarn setup.
• Relax website dependency constraints to reduce the number of unnecessary Renovate PRs.
• Switch GitHub Actions to major-version tags for the same reason (only typos, for actionlint it isn't possible, unfortunately).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.98%. Comparing base (2179ec9) to head (5ddcb9f).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #747   +/-   ##
=======================================
  Coverage   81.98%   81.98%           
=======================================
  Files          46       46           
  Lines        2681     2681           
=======================================
  Hits         2198     2198           
  Misses        483      483           

Flag	Coverage Δ
integration	56.13% <ø> (ø)
unit	67.92% <ø> (ø)

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