DOC: Add comprehensive Google Colab data loading guide

[kalluripradeep]

Description

Closes #62708

This PR adds a comprehensive Google Colab data loading guide to the IO documentation, addressing the need for clear, cohesive documentation on loading data in Google Colab environments.

Changes

Added a new "Google Colab" section to doc/source/user_guide/io.rst covering:

1. Reading from Google Drive - Mounting Drive and accessing files
2. Uploading files directly - Using the upload widget
3. Reading from URLs - Loading data from GitHub and other web sources
4. Reading from Google Sheets - Using export URLs
5. Reading Kaggle datasets - Authentication and download process
6. Best practices - Recommendations for different use cases

Key Features

• Comprehensive coverage: Goes beyond existing PR Add Google Colab IO instructions to pandas IO documentation #63102 by including Google Sheets, Kaggle datasets, and best practices
• Multiple file formats: Examples for CSV, Excel, JSON, and Parquet
• Well-structured: Proper RST formatting with anchors, code blocks, and notes
• User-focused: Practical examples with clear explanations
• 154 lines of documentation vs 33 lines in competing PR

Comparison to Existing PRs

This PR provides significantly more comprehensive documentation than PR #63102 (which has been open for 2 weeks without review):

• ✅ Includes Google Sheets integration (missing in Add Google Colab IO instructions to pandas IO documentation #63102)
• ✅ Includes Kaggle datasets workflow (missing in Add Google Colab IO instructions to pandas IO documentation #63102)
• ✅ Includes best practices section (missing in Add Google Colab IO instructions to pandas IO documentation #63102)
• ✅ Examples for multiple file formats (only CSV in Add Google Colab IO instructions to pandas IO documentation #63102)
• ✅ Proper RST formatting with section anchors
• ✅ Well-organized with subsections

Testing

• Verified RST formatting renders correctly
• Tested code examples work in Google Colab
• Added changelog entry to doc/source/whatsnew/v3.0.0.rst
• Follows pandas documentation style guide

References

• Original issue references Polars documentation as inspiration
• Addresses maintainer feedback about wanting cohesive Colab documentation