Try Infura node for authentication

Since we have no local auth nodes on trappist-one server, it's interesting to try Infura for authentication.

It requires a bit different auth process:

1. No auth module enabled on public endpoints;
2. We have to deploy auth smart contract via signed transaction and the fact of successful deployment proves the initial authentication;
3. We use newly deployed smart contract address for further access/refresh token updates.

The idea of Infura usage — on low-resource trappist-one server we do not run auth Geth node instance. So signer instance is unavailable as well.

To sign transactions locally Bitcoin::Core::Secp256k1 module should be used.