update requirements.txt
ask for permission to access list of friends
add ``friends`` app
add stolen ``social_friends_finder`` app
configure friends fetching
Merge branch 'feature/social_friends_finder' into develop

* feature/social_friends_finder:
  configure friends fetching
  add stolen ``social_friends_finder`` app
  add ``friends`` app
  ask for permission to access list of friends
  update requirements.txt