pre-commit add chmod 644 manual hook for Markdown

[jbampton]

Description

This PR adds a manual hook that can be used in a full repo clean up on a local machine.

See some of my discussion about manual hooks here:

refs apache/cloudstack-www#362

So Windows users don't normally have the chmod command so this hook can be run by macOS and Linux users when needed. And I have also added this to the CI with a --hook-stage manual run so we don't lose coverage.

In future we can add more manual stage hooks.

Some other ASF projects that use the hooks from Lucas-C are Apache Sedona and Apache Airflow:

https://github.com/apache/sedona/blob/6029bec540e11b52d0a21819e23db6f4001cec94/.pre-commit-config.yaml#L78

https://github.com/apache/airflow/blob/ec758b7abf189d5027e830d91effa85e17659249/.pre-commit-config.yaml#L50

Also I added Lucas-C hooks to mruby:

https://github.com/mruby/mruby/blob/437b47dca7ce8a2bf8a660dbbd920caa33c14794/.pre-commit-config.yaml#L69

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• build/CI
• test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

Ran pre-commit and all the hooks locally

How did you try to break this feature and the system with this change?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 17.39%. Comparing base (96ccd7e) to head (489e528).
⚠️ Report is 24 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #11651      +/-   ##
============================================
- Coverage     17.39%   17.39%   -0.01%     
+ Complexity    15283    15282       -1     
============================================
  Files          5889     5889              
  Lines        526141   526141              
  Branches      64234    64234              
============================================
- Hits          91542    91532      -10     
- Misses       424265   424275      +10     
  Partials      10334    10334              

Flag	Coverage Δ
uitests	3.62% <ø> (ø)
unittests	18.44% <ø> (-0.01%)	⬇️

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[github-actions]

This pull request has merge conflicts. Dear author, please fix the conflicts and sync your branch with the base branch.