feat: add config option for line length warning

[Lee-W]

Description

This PR implements configuration file support for the message_length_limit option, addressing issue #1571 . Previously, users could only set commit message length limits via command-line arguments (-l/--message-length-limit). Now they can define a default limit in their configuration file.

Checklist

• I have read the contributing guidelines

Code Changes

• Add test cases to all the changes you introduce
• Run poetry all locally to ensure this change passes linter check and tests
• Manually test the changes:
  • Verify the feature/bug fix works as expected in real-world scenarios
  • Test edge cases and error conditions
  • Ensure backward compatibility is maintained
  • Document any manual testing steps performed
• Update the documentation for the changes

Documentation Changes

• Run poetry doc locally to ensure the documentation pages renders correctly
• Check and fix any broken links (internal or external) in the documentation

Expected Behavior

Users can now set default commit message length limits in their configuration file:

[tool.commitizen]
message_length_limit = 72

Steps to Test This Pull Request

1. Test Configuration File Support

# Add the following to your pyproject.toml:
[tool.commitizen]
message_length_limit = 30

# Test with long message (should fail)
cz check -m "fix: this is a very long commit message that exceeds 30 characters"

# Test with short message (should pass)  
cz check -m "fix: short message"

2. Test CLI Override

# CLI argument should override config setting
cz check -m "fix: this message is longer than 30 chars but shorter than 60" -l 60

# Disable limit with CLI
cz check -m "fix: very long message that would normally fail config limit" -l 0

Additional Context

[Lee-W]

revive #1574

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.25%. Comparing base (120d514) to head (f3e22fb).
⚠️ Report is 802 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1590      +/-   ##
==========================================
+ Coverage   97.33%   98.25%   +0.91%     
==========================================
  Files          42       58      +16     
  Lines        2104     2695     +591     
==========================================
+ Hits         2048     2648     +600     
+ Misses         56       47       -9     

Flag	Coverage Δ
unittests	98.25% <100.00%> (+0.91%)	⬆️

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