Enable export of csv in mobile

[greenaddress]

Mobile app doesn't support csv export of address book or history. It is disabled on purpose because it requires more integration with the environment to save the file.

Enable it and fix column currently showing satoshi to be consistent with the selection in the UI/profile (btc, mbtc, etc)

A plugin is probably necessary to handle the file saving on both Java and ObjectiveC for respectively Android and iOS.