build: add commitizen to pre-commit and document guidelines

[AleNunezArroyo]

Overview: What does this pull request change?

This pull request integrates Commitizen into the pre-commit workflow and provides documentation for the repository's commit message format guidelines.

Specifically, it:

• Configures Commitizen rules (types, scopes, and examples) inside pyproject.toml.
• Adds the commitizen hook under the commit-msg stage in .pre-commit-config.yaml.
• Creates a comprehensive commit guidelines document at docs/source/contributing/commits.md.
• Updates the references in docs/source/contributing/development.md to link to the new guidelines.

Motivation and Explanation: Why and how do your changes improve the library?

This change enforces consistent and descriptive commit messages conforming to the Conventional Commits specification. Having structured commits enables automated changelog generation, better readability of the project history, and easier semantic versioning management.

Links to added or changed documentation pages

• docs/source/contributing/commits.md
• docs/source/contributing/development.md

Further Information and Comments

Closes #4748

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested