Implement Group Chat Functionality

The primary objective of this issue is to introduce the crucial feature of group chat functionality into our Flutter chat app. Currently, our app allows users to engage in one-on-one conversations, but the time has come to take it a step further and embrace group chats. This enhancement will add a layer of dynamism and interactivity to our application, providing users with the ability to create, join, and efficiently manage group chats, all within a user-friendly and intuitive interface.
The proposed solution involves the following key components:

**1. *Creating Group Chats:*** Users should be able to create new group chats, define the chat's name, description, and set privacy settings. This includes determining whether the group is open for anyone to join or if it requires an invitation.

**2. *Sending Messages:*** Within group chats, users should have the capability to send messages that are visible to all participants. The message sending mechanism should be seamless and user-friendly, supporting text, media, and attachments.

The implementation of group chat functionality is a foundational step in making our app more versatile, enabling users to connect with multiple individuals simultaneously, foster community interaction, and enhance the overall experience for both new and existing users. This feature will greatly enrich the social and communication aspects of our application, aligning it with the expectations of modern chat apps. It's a valuable addition that will likely be appreciated by our user base.