Zelf Wallet - Android Offline Create Random Zelf Name

[carlosbleck]

Description

Make Zelf Offline Version totally usable without Internet Connection for Onboarding Flow (Create and Import Wallet)

Todo

• [x] New flow on Android Offline version when creating or importing a new wallet.
• [x] A new random name with the form of zoff····· is created avoid duplicates on IPFS system.
• [x] Return Onboarding screens to the old design.

[johsecaba]

QA succesful!