fix(devnet): compatibility with upcoming mpc node version 3.0.0

[kevindeforth]

resolves #521
requires https://github.com/Near-One/infra-ops/pull/503
related follow-ups:

• Devnet cleanup after 3.0.0 release. #710
• Display responder_account_id and mpc_account_id on public data endpoint #712

changes:

• deploy-contract command is now split into two commands deploy-contract (deploy the code) and init-contract (initialize the contract).
• add-keys method, adding the public keys generated by the nodes to the mpc and responder accounts (signer and responder keys).
• unused --max-requests-to-remove argument has been removed from the contract commands
• devnet no longer panics upon calling describe in case the contract is not initialized:

thread 'main' panicked at devnet/src/mpc.rs:812:10:
Expected rpc node to respond: ServerError(HandlerError(ContractExecutionError { vm_error: "wasm execution failed with error: HostError(GuestPanic { panic_msg: \"Calling default not allowed.\" })", block_height: 206548722, block_hash: 2LPrNt4BEv2MU6GVRRCZLYXvD1dCUYFRymr5mXtdYWZC }))
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[netrome]

Started reviewing. One question mark so far. Will continue tomorrow morning.

[netrome]

Thanks for fixing devnet 🙏