Task 120: Generate mock data for request_guest_details and req_add_info

[sanskrutichavanke]

Contributor: Sanskruti

This PR adds mock data generation for:

• request_guest_details
• req_add_info

Key points:

• Generates up to 100 rows per table
• Maintains relationships using request_id and cat_id
• Uses Faker for realistic data
• Uses lookup tables for valid values

Also includes:

• Updated README
• Generated CSV files in database/mock_db