Add Register Indentity command

[pshenmic]

Issue

We need a way to register an identity in the application. It is done via providing a private key from the address with the DASH balance, which will be used to register an identity in Dash Platform and fund initial credit balance.

The command crafts and broadcast signed AssetLock transaction in the Core network, and then uses the InstantLock (ChainLock) proof to create a IdentityCreateStateTransition in the Dash Platform network.

Operation involves creating transactions in two network (Core, Platform)

Things done

• Serialize & Sign Core AssetLock transaction

[pshenmic]

It is not possible to achieve that at this time, because InstantLock / ChainLock data that is needed to create IdentityCreateTransition in Platform only available from the Core ZMQ interface, and it basically blocks implementation, because platform-cli relies on DAPI endpoint.

There is a support of InstantLock messages in the DAPI via subscribeToTransactionWithProofs query, but it work through BloomFilter, which does not have an implementation in the rust-dashcore and thus we can't use that method.

Other indexing services like Insight API, or rpc.digitalcash.dev, also does not provide that information, because Core itself does not have such data in the RPC

The best scenario, if Core could implement instant lock \ chainlock buffer data in one of the RPCs, so we could easily fetch that via HTTP gateways.

Another approach would be to implement a separate, hosted service, that will allow you to subscribe on transactions and return you instantlock data that has access to Core ZMQ, but this gotta be done as a separate project (f.e. https://github.com/maxmanukian/dash-websocket)