[CI] Add pre-commit hook markdownlint with basic config

[jbampton]

Setup very basic config file with a lot of rules disabled.

https://github.com/davidanson/markdownlint#rules--aliases

Uses the Command Line Interface for markdownLint

https://github.com/igorshubovych/markdownlint-cli

Used on Apache Shiro and Airflow:

https://github.com/apache/shiro/blob/638d011a8e90ff500754b4d2f63b0746a2e3c624/.pre-commit-config.yaml#L102

https://github.com/apache/airflow/blob/6877aea6353cd0d54a622a6d7dcb4157888db060/.pre-commit-config.yaml#L1007

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Using markdownlint within a pre-commit framework on GitHub prevents poorly formatted or broken documentation from entering your codebase by catching errors locally before code is pushed. It enforces stylistic consistency across files like README.md, turning manual style validation into an automated check.

Key Benefits

• Enforces Document Consistency: It eliminates conflicting styling choices (like mismatched heading levels or inconsistent indentation) across contributors, producing cohesive documentation.
• Reduces Code Review Noise: Reviewers can skip nitpicking about markdown formats or spacing in Pull Requests, shifting human focus strictly to content substance and accuracy.
• Saves CI/CD Build Time: Catching errors locally at the moment of a commit means you do not have to wait for a GitHub Actions workflow to run, fail, and require a fix.
• Prevents Broken Renderings: It detects parsing inconsistencies before they reach GitHub, ensuring documentation renders beautifully without broken elements on repository homepages.
• Optimizes Content for AI: Standardised Markdown makes it much easier for AI coding tools and LLMs to correctly ingest, parse, and comprehend your repository's documentation.
• Automated Error Fixing: When paired with formatting commands, it can automatically fix common layout issues (like missing trailing whitespaces) right during the commit process.