[iOS][FEATURE 65]Implement Invite Friends page

Feature 35: Implement "Invite Friends" page

- Trello: https://trello.com/c/woHUx3ko/51-16-35-implement-invite-friends-page
- Test case: https://docs.google.com/spreadsheets/d/1YXhKNi3YODCGg-Fk817K_Jk7gmM0Nhkie6RWptWEJww/edit#gid=0