Add `CODEOWNERS` file to automatically request reviews and speed up PR review time

https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners

A CODEOWNERS file is a powerful tool for defining which individuals or teams are responsible for specific files or directories in a repository. Using one offers several key benefits for team collaboration and code quality:

* Automated Review Assignments: When a pull request (PR) is opened, the system automatically identifies and requests reviews from the correct owners based on the files changed. This eliminates the need for developers to manually track down who should review their work.
* Enforced Expert Approval: By combining CODEOWNERS with branch protection rules, you can require an approval from at least one designated owner before a PR can be merged. This ensures that changes to critical or complex code areas are always vetted by someone with domain expertise.
* Enhanced Security: It acts as a safeguard against unauthorized or accidental changes to sensitive files, such as configuration or security-related code.
* Clear Accountability: The file serves as a single source of truth for who is responsible for different parts of the codebase. This transparency helps new team members during onboarding and clarifies who to contact for specific bug fixes or improvements.
* Faster Development Cycles: In large teams or monorepos, automated routing of PRs reduces delays caused by "reviewer spam" or pinging the wrong people. It also helps keep teams up-to-date on changes happening in the code they specifically own.
* Code Stability: Because code owners are invested in their specific areas, they are more likely to catch potential issues early, enforce consistent coding styles, and prevent "code rot".

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Example Apache Airflow CODEOWNERS file:

https://github.com/apache/airflow/blob/main/.github/CODEOWNERS

See the following issue on CloudStack for some example images of how it worked on Airflow and for CloudStack:

refs https://github.com/apache/cloudstack/issues/11646

Start with GitHub's CODEOWNERS documentation and the linked Apache Airflow .github/CODEOWNERS example. Then determine which Lucene.NET paths and owners should be mapped; done means an agreed .github/CODEOWNERS file requests appropriate reviews for relevant pull requests.

Written by the indexing model from the issue text.