Refactor AttendeeFragment

[iamareebjamal]

Several issues with AttendeeFragment

• Too large
• Does not follow MVVM.
• Handles complex logic like payments itself
• Has unnecessary logic in it
• Uses strings heavily instead of resources

[liveHarshit]

I want to work on it.

[liveHarshit]

Payment condition is also written wrong, It goes for the payment without checking attendee created successfully or not. (If user details are blank). Should I fix it in this issue or in a new one?

[iamareebjamal]

Each small issue should be created first and then fixed. So create an issue and mention this as a parent