Added new features/fixed bugs.

- Replaced hardcoded token with a prompt.
- Allowed dynamic input for multiple channel IDs.
- Added random delay between sending messages/files to avoid rate limits.
- Integrated logging to track sent messages and errors in a log file.
- Improved error handling and retries for rate limits (HTTP 429).
- Fixed some minor bugs with message sending.

Update selfbot.py

version 0.3.0-alpha

Update README.md

Changed the readme to match the new code, and updated the todo list.