Refactor UploadActivity

[ashishkumar468]

Summary:
The current flow of UploadActivity has a lot of code in a single place, because of which it is very difficult to find bugs and is very difficult to maintain the code. As a part of adopting the MVP pattern, refractor the Upload Activity to use MVP and switch to fragments instead of the entire code being in the single Activity forcing the Activity to juggle views (inside the ViewFlipper, adding complexity). Also solve #2832

Would you like to work on the issue?
Yes