BIP38 Support (when using private key to create+sign tx)

[chill117]

CryptoTerminal is able to read a private key via the device's camera or NFC reader. But currently this is limited to unencrypted private keys. Support should be added for BIP38.

BIP38 is a standard process to encrypt Bitcoin and crypto currency private keys that is less susceptible to brute force attacks thus protecting the user.

See:
https://github.com/bitcoinjs/bip38