docs: Updated coding guidelines and added skills documentation

- Updated .github/CODING_GUIDELINES.md to include new coding standards and best practices.
- Updated .github/copilot-instructions.md to provide clearer instructions for using GitHub Copilot effectively.
- Added .github/skills/README.md to introduce the new skills documentation and provide an overview of the available skills.
- Added .github/skills/add-component-property/SKILL.md to document the process of adding a new property to a component.
- Added .github/skills/create-new-component/SKILL.md to document the steps for creating a new component from scratch.
- Added .github/skills/review-component-pr/SKILL.md to outline the best practices for reviewing pull requests related to components.
- Added .github/skills/update-component-styles/SKILL.md to guide developers on how to update the styles of existing components while maintaining consistency with the design system.

Author: rkaraivanov