Sign message malfunction.

[kraikov]

https://github.com/liquality/chainabstractionlayer/blob/989e97f6c0931a289cd76b66c997165be21f3256/packages/bitcoin-js-wallet-provider/lib/BitcoinJsWalletProvider.js#L53

1. You should pass message prefix when signing messages - '\u0018Bitcoin Signed Message:\n'

2. You have to take into account what type is the address signing the message i.e. if it's segwit you should pass { segwitType: 'p2wpkh' }

3. You need to encode the string as base64 in order to be able to verify it.

[kraikov]

@monokh shall we fix that?