feat: simple user api to extract html to markdown

[drunkpig]

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Motivation

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Modification

Please briefly describe what modification is made in this PR.

BC-breaking (Optional)

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If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

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Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects.
• CLA has been signed and all committers have signed the CLA in this PR.

[codecov]

Codecov Report

Attention: Patch coverage is 95.55556% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
llm_web_kit/config/cfg_reader.py	87.50%	1 Missing ⚠️
llm_web_kit/simple.py	97.05%	1 Missing ⚠️

@@            Coverage Diff             @@
##              dev     #313      +/-   ##
==========================================
+ Coverage   89.96%   90.09%   +0.12%     
==========================================
  Files          82       84       +2     
  Lines        5581     5644      +63     
==========================================
+ Hits         5021     5085      +64     
+ Misses        560      559       -1     

Files with missing lines	Coverage Δ
llm_web_kit/extractor/html/extractor.py	92.66% <100.00%> (ø)
llm_web_kit/libs/logger.py	96.96% <100.00%> (ø)
llm_web_kit/model/resource_utils/utils.py	96.55% <100.00%> (ø)
llm_web_kit/config/cfg_reader.py	92.85% <87.50%> (+11.90%)	⬆️
llm_web_kit/simple.py	97.05% <97.05%> (ø)

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