Have multiple referred friend before completing the "Refer a friend" activity

[aurelticot]

### Tasks
- [ ] Define a constant for the number of referrals to acheive
- [ ] Check the number of referral confirmation message received to complete
- [ ] Update the UI to display the information (number of referrals received, number to go, etc.)

[ysam21]

I'd like to propose that each referral will result in XP earned, up to a max limit.
i.e. 1 referral = 50 XP, 2 referrals = 100 XP... up to 5 referrals = 250 XP

[aurelticot]

I'd like to propose that each referral will result in XP earned, up to a max limit. i.e. 1 referral = 50 XP, 2 referrals = 100 XP... up to 5 referrals = 250 XP

This is not how the logic for XP points is implemented at the moment.