[Feat] Add the ability to request to join closed servers

[abi-sheks]

Is your feature request related to a problem? Please describe.
Currently, users cannot request to join closed servers, which means if a server is private or closed, they have no way to ask for access.

Describe the solution you'd like
Introduce a feature that allows users to request to join closed or private servers. This functionality should:

• Allow users to send a join request to closed servers using a command like request-join <server_name>.
• Notify the server owner or moderators about the join request, including the requesting user's details.
• Provide server owners and moderators with the option to approve or deny requests.