Improve error handling

[franciszekjob]

Which component is your feature related to?

Cast

Feature Request

In the scope of this issue, we should:

• add displaying content of unknown error
• handle other errors coming from starknet-rs, e.g. having such example in which we declare a new contract with sncast and we don't provide max-gas, we receive "Unknown RPC error", even though the real error is FeeOutOfRange coming from starknet-rs

[cptartur]

We can probably remove the whole starknet-rs to ours errors mapping or at least simplify it.