[Feat] Add a friend system

[abi-sheks]

Is your feature request related to a problem? Please describe.
There is currently no way to keep track of users of interest other than to remember their usernames.

Describe the solution you'd like
Add a friend system, using which you can send a friend request to someone, and accepting which they can become your friend. Add the option to view all incoming friend requests and commands to accept or reject them. Add the ability to list out all friends.