Ditch the concept of friends and replace it with followers

[NathanPB]

The "friends" concept requires that both users take actions (send invite, accept invite) to stablish a connection between then. Using a concept of "following and followers" will help the users to get engaged with each other without having to wait (and hope) until the other user accept his invite.

This will also help with the data model structure that currently requires to perform updates in two profile documents when a request is sent.

Also, no more "friendRequests" collection bye bye

This is why I'm getting away from "friends" and starting with "followers"

Tasklist

• Implement it in the backend (always easier...)
• Remove the old "friends" code
• Implement in the webapp
• Change that icon of the heart that does not want to go filled
• Make a page to see the full list of followers/following of a user. With lazy loading
• Ship it =)

[NathanPB]

Closing this as this is done =)