🎯 Added solution for Real Image Challenge 2016

[mridulpuri]

This PR includes the implementation of the Real Image Challenge 2016 in Go. The solution follows a hierarchical permission system where:

• Cities and distributors are loaded from CSV files (cities.csv, distributors.csv).
• Authorization is checked recursively, ensuring each distributor’s permissions are a subset of their parent’s.
• Exclusions override inclusions, and permissions are inherited correctly.
• Input is normalized (case-insensitive, space-trimmed) for accurate matching.
• Detailed authorization reasons are provided when checking a region.