Add main.py for file management system with tries

[shubhambhar007]

Add main.py for file management system with tries
The new file includes:

Features:

• Add files and directories
• Search for files/directories
• Path existence checking
• Prefix searching
• Autocomplete functionality
• Directory listing
• File deletion
• File content storage and retrieval

All operations include detailed time and space complexity analysis:

• Insert: O(n) time, O(n) space
• Search: O(n) time, O(1) space
• Autocomplete: O(n + mk) time, O(mk) space
• List Directory: O(n + m) time, O(m) space
• Delete: O(n) time, O(1) space

[shubhambhar007]

@ashishps1 requesting your kind review on this.
Please let me know if you would prefer breaking it into modules or if this boilerplate is sufficient.