Prefix all on-chain error messages with contract/namespace

[krebernisak]

We should prefix all error messages with contract/namespace like so:

    with_attr error_message("Aggregator: Total amount due exceeds the balance"):

Originally posted by @krebernisak in https://github.com/smartcontractkit/chainlink-starknet/pull/146#discussion_r989988962

[krebernisak]

We should also standardise the error language: https://github.com/OpenZeppelin/cairo-contracts/issues/488