docs: align API reference package name with PyPI

[vdusek]

The package name is rendered as the label on the docs website API reference pages, so this renames it (apify-sdk-python-website / older apify-sdk-python) to apify (the PyPI package), across all versions.

@B4nan tagging you as a reviewer since you changed this recently — let me know if there was any reasoning behind it that I'm missing.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.94%. Comparing base (24a6edb) to head (ab2bb54).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #940   +/-   ##
=======================================
  Coverage   86.94%   86.94%           
=======================================
  Files          48       48           
  Lines        2942     2942           
=======================================
  Hits         2558     2558           
  Misses        384      384           

Flag	Coverage Δ
e2e	37.76% <ø> (+0.20%)	⬆️
integration	59.10% <ø> (+0.20%)	⬆️
unit	75.69% <ø> (ø)

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