Feature/user visibility

[sinansoulier]

Added privacy features:

• Updated User model :

  • Indicate through a boolean flag if a user is completely anonymous (or not)
  • Added list of users (per user) to whom profile visibility is given.

• Added routes :

  • POST | /users/{id}/updateVisibility: Makes a user visible or invisible to all other users based on the given user ID
  • POST | /users/{id}/makeVisible: Makes a user visible to other users based on the given user ID
  • POST | /users/{id}/makeInvisible: Makes a user invisible to other users based on the given user ID