Implement a SHA256 based brain wallet lookup

[bernardladenthin]

Provide an implementation which reads rows of a file and create sha256 hash which is used as private key.

See:

• https://brainwalletx.github.io/
• https://allprivatekeys.com/brain-wallet-cracker

Word-Lists:

• https://github.com/dwyl/english-words

[bernardladenthin]

It's implemented. For example, refer to: https://github.com/bernardladenthin/BitcoinAddressFinder/blob/ad9f09343659a75c4444480225be63a091f4fc00/examples/config_Find_SecretsFile.js. The mode for pre-hashed SHA256 values is set to "SHA256".