The functions in this file should be factored out to a separate utility lib as they are reused in bitcoin-etl https://github.com/blockchain-etl/ethereum-etl/blob/develop/ethereumetl/misc_utils.py

Describe the bug
The Send, Receive and Camera screens use the modal mode of react-navigation. The use of a cross icon in the top right corner of the screen is more suitable than using a back arrow on the top left corner of the screen.

To Reproduce
Steps to reproduce the behavior:

1. Create a new wallet
2. Click on 'Send' or 'Receive'
3. See