[ADD] Multiplatform .gitignore & Spanish version README.

[SebaMat3]

This PR introduces a .gitignore for multi-platform development and a fully translated version of the README file into Spanish, aimed at improving accessibility for Spanish-speaking users. The translation maintains the original formatting, Markdown structure, and links to ensure consistency and ease of navigation.

Changes Made:

Add comprehensive .gitignore for multi-platform development

Added a .gitignore file that covers:

• OS-specific files for Linux, macOS, and Windows
• Common system and temporary files
• IDE and backup files

This will help keep the repository clean across different development environments.

Added a Spanish version of the README with a detailed explanation of code2prompt, including:

• Features
• Installation instructions
• Usage examples
• Templates
• User-defined variables
• Tokenizers
• Contribution guidelines
• Licensing information

All links, headings, and Markdown formatting have been preserved to align with the original README structure.

Why This is Useful:

Spanish is one of the most widely spoken languages globally, and providing documentation in Spanish broadens the reach and usability of code2prompt to a larger audience.
It helps Spanish-speaking developers and users better understand and utilize the tool without language barriers.

How to Test:

• Open the README.md file and verify the accuracy of the translation.
• Confirm that all links redirect correctly to their respective resources.
• Check the formatting for consistency with the original English README.

Additional Notes:

This translation sets a foundation for potential future multilingual support for the project. Feedback on the translation quality or any improvements is welcome!