Feature: Restore Wallet with QR-Code

[jenniferberger]

As a user i want to restore my wallet using QR-codes to quickly enter the keys without errors.

Currently the createwallet from * activities require me to enter the private key without input support. I have to copy&paste from a file to save time.

The public key input should have the [scan] button using the existing ScannerFragment
The complete wallet should be scanned with a code that can contain &seed=text&v_key=view_key&s_key=spend_key&min_height=0

Currently moneroaddress.org does not specify a format for seed, v_key, s_key or min_height and only exposes the public key as QR-code. There is a issue (#12) that requests paper wallets. The fix to that that could include the private keys as well (as they make sense on paper).

[jenniferberger]

Updated the https://github.com/monero-project/monero/wiki/URI-Formatting wiki entry and added a pull-request moneromooo-monero/monero-wallet-generator#15