Fix bugs and add group functionalities

This release added :

• update to whatsapp_bot_platform_interface 1.0.0
• Breaking change: new way of listening to messages: client.on(WhatsappEvent.chat_new_message, (data) => print(data));
• add support for listening to multiple events
• fix delete message
• add option to send file name in sendFileMessage
• add more methods to WhatsappClient.chat