Canonicalize `foc-devnet` SetupContext, ContractAddresses and Wallet keys

[redpanda-f]

As part of #7, it is necessary that we present a stable set of keys that external tools can expect while interacting with foc-devnet. Currently, ad-hoc key-value pairs are being used for contract addresses, keys and SetupContext. We need to fix them properly, to allow for easier use by external tooling.