BREAKING CHANGES: 4.0.0-a1

[showierdata9978]

• Enhanced userlist functionality to utilize actual User objects rather than string representations of usernames.
• Implemented a dedicated API for bot checking, leading to improved code organization and reliability.
• Rectified the post condition to operate correctly, resolving a prior issue where it erroneously shared functionality with the packet condition.
• Removed the 'bot' object from the 'Context' class, opting for streamlined interactions via the bot checking API.
• Adopted Pythonic naming conventions by renaming the 'sendPacket' method to 'send_packet' within the 'Client' class.
• Adjusted the timing of the '__raw__' callback invocation, substituting its previous use with the more appropriately named 'raw_message' callback.