Add functions to decode reject reason in contract client

[DOBEN]

Purpose

Add methods to the ContractClient to decode the reject reason for a failed transaction during dry-run.
Related Concordium/concordium-dapp-examples#87

Changes

• Update the ContractClient to optionally keep track of the associated schema of the contract.
• Update the create method to the ContractClient to look up the embedded schema from the chain.
• Add the new_with_schema method to the ContractClient to create a ContractClient with a given schema.
• Add dry_run_update_with_reject_reason_info and dry_run_update_raw_with_reject_reason_info methods to the ContractClient. They are like the dry_run_update and dry_run_update_raw methods but in case of a reject, decode the reject reason into a human-readable error.
• Add decode_concordium_std_error and decode_smart_contract_revert functions to facilitate reject reason decoding of failed transactions.

[soerenbf]

Very nice write-up of the error decoding rationale 😄

I still have one suggestion originating from @limemloh as seen below:

Otherwise I think it looks good 👍