docs: move intermediate ASGI tutorial code to versioned examples

[sonephyo]

Summary of Changes

• Moved Python codes within docs/user/tutorial-asgi.rst to examples/asgilook.
• Refactored examples/asgilook from the final version of code to a different version of code.
• Organized versions of codes relating to the example checkpoints (e.g., 01_basic/, 02_dynamic_thumbnails/, 03_caching/, etc.)
• Fixed incorrect logging example in "Debugging ASGI Applications" section, which was previously showcasing WSGI logging example. examples/asgilook/01_basic/asgilook/logging.py

Related Issues

Closes #2247

Pull Request Checklist

This is just a reminder about the most common mistakes. Please make sure that you tick all appropriate boxes. Reading our contribution guide at least once will save you a few review cycles!

If an item doesn't apply to your pull request, check it anyway to make it apparent that there's nothing to do.

• Applied changes to both WSGI and ASGI code paths and interfaces (where applicable).
• [] Added tests for changed code.
• Performed automated tests and code quality checks by running tox.
• Prefixed code comments with GitHub nick and an appropriate prefix.
• Coding style is consistent with the rest of the framework.
• Updated documentation for changed code.
  • Added docstrings for any new classes, functions, or modules.
  • Updated docstrings for any modifications to existing code.
  • Updated both WSGI and ASGI docs (where applicable).
  • Added references to new classes, functions, or modules to the relevant RST file under docs/.
  • Updated all relevant supporting documentation files under docs/.
  • A copyright notice is included at the top of any new modules (using your own name or the name of your organization).
  • Changed/added classes/methods/functions have appropriate versionadded, versionchanged, or deprecated directives.
• Changes (and possible deprecations) have towncrier news fragments under docs/_newsfragments/, with the file name format {issue_number}.{fragment_type}.rst. (Run tox -e towncrier, and inspect docs/_build/html/changes/ in the browser to ensure it renders correctly.)
• LLM output, if any, has been carefully reviewed and tested by a human developer. (See also: Use of LLMs ("AI").)

If you have any questions to any of the points above, just submit and ask! This checklist is here to help you, not to deter you from contributing!

PR template inspired by the attrs project.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (73b7637) to head (0874a1b).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #2563   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           64        64           
  Lines         7860      7860           
  Branches      1076      1076           
=========================================
  Hits          7860      7860           

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