Introduce build_deploy_transaction function on Contract

[mpoplavkov]

close #1305

This PR doesn't exactly solve the issue, but adds a possibility to get the tx id from the built transaction. I didn't want to change the deploy method signature, cause it'll trigger changes in the whole project.

So, the proposed solution to get the tx id is:

let tx = contract.build_deploy_transaction(account, tx_policies).await?;
let tx_id = tx.id(provider.chain_id());
contract.deploy(account, tx_policies).await?;
println!("Deployed contract at tx: {}", tx_id.to_string());

However, I'm not sure if that's correct, cause in that flow the deploy transaction will be built twice (by calling build_deploy_transaction and then deploy), so potentially these two transactions might differ. Let me know what you think